1. Introduction Learning a foreign language is a very complex process that depends on various elements such as student, teacher, teaching method, etc. Among these elements, however, the element of teaching method plays a decisive role in the state of education, and it influences the other elements as well. Therefore, it is very important to use a practical and effective teaching method. One of the methods that has been proposed in recent decades and has received much attention in foreign language teaching is the task-based teaching approach. This approach, as a new approach that stems from the communicative approach in language teaching, is based on tasks/ a task. In defining a task, Ellis (Ellis. 2004. p. 9-10) refers to a set of essential features and believes that,a task is a work plan (1),the main focus is on meaning,has real processes in the use of language,can include any of the four language skills,involves cognitive processes,and it has a very clear communicative result. Therefore, it can be said that the main purpose of this teaching method is to increase language learners’,communicative ability through tasks that are based on meaning and reality. In this method language is taught in three stages of pre-task, during task and post-task. 2. Materials and methods Although this approach has been regarded as a highly effective and practical approach in foreign language teaching, its effectiveness in teaching Arabic listening skill, which is a basic skill in learning Arabic language and which requires a practical and effective method of teaching and learning, has not yet been investigated. Therefore, this study, with the aim of facilitating the learning process and increasing language learners’,listening comprehension ability, intends to empirically examine the effectiveness of the task-based approach in enhancing language learners' listening comprehension. To this end, first, the topic has been analyzed and examined theoretically and its basic principles have been explained thoroughly. After that, to measure the effectiveness of this approach in teaching listening skill, the approach has been implemented practically. To implement this teaching model, first an educational booklet which consisted of 10 lessons along with their audio files was prepared to be used in the implementation stage of this teaching method. The booklet was designed in accordance with the main principles of task-based approach. In the next step, 30 undergraduate students of the University of Tehran were randomly selected and 15 of them were randomly placed in the control group and the other 15 in the experimental group. Of course, due to the absence of a number of students in the post-test, the statistical sample of the present study was reduced to 13 people in each group. Prior to implementation of the project, to ensure the homogeneity of the groups, an identical pre-test was administered by a third party to both groups under the same conditions. After ensuring the homogeneity of the groups, the experimental group was taught for 16 two-hour sessions (which is equivalent to one academic semester) according to this approach, using the teaching package that was developed. At the end of the teaching sessions, an identical post-test was administered by a third party to both groups under same conditions. Finally, the test results of both groups were investigated using version 26 Of SPSS software. 3. Results and discussion The data of this study were analyzed by conducting both descriptive and inferential statistics. Descriptive statistics such as frequency, mean percentage, and standard deviation and the inferential statistic of t-test were used. An examination of the descriptive statistics showed that the mean score of the experimental group in the post-test was higher than in the pre-test. However, there was no significant change in the mean score of the pre-test and the post-test of the control group. Also, t-test results showed that the P value in the control group was above (0. 05) and the difference was not significant. Nevertheless, the P value in the experimental group was less than (0. 05) which shows that the difference in performance of the participants in this group was significant and real. The independent variable (teaching listening skill based on TBLT approach) has significantly caused a remarkable growth in the dependent variable (the extent of the enhancement in the Arabic listening comprehension ability). 4. Conclusion The research hypothesis that claims a positive and significant effect of task-based approach on the development of the language learners’,listening comprehension was confirmed. In addition, according to the research data, it can be explicitly claimed that the task-based teaching model that is based on interaction and that emphasizes the real activities similar to what the language learner encounters in real situations, can be regarded as one of the effective methods for increasing language learners' listening comprehension ability in teaching listening courses to Arabic language students in the laboratory.