Man-Machine interaction is an issue that requires great attention; otherwise, it would affect the effectiveness and efficiency of activities of the systems (machine) and could cause disorder on their working procedure. Legal, political and technical complexities on one hand and human differences in attitudes, beliefs and values on the other hand, have a great influence on the effectiveness of decision making in VTS operating. Today, a great number of regulations are developed or under development about marine safety issues, marine environment protection and marine security at international and national level dimensions; thereupon, workload of VTS operators is increased. In this regard, we are facing “Safety-Based” rules and regulations from international bodies, mainly IMO, IHO, IALA, in which the end users are humans who are doing the job. However, due to the lack of harmonized concept from same subject, there are uncertainties while operating VTS.There are questions to be asked about the actual situation of gathered, recorded, analyzed and processed information for supporting decision making on safety and environmental protection.These questions should be understood in “based on conceptualization” which is never an “objective world” and till there is no enough clarity for understanding the same concepts and suitable cooperation (e.g., technical, political, and managerial and ….), the whole potential of VTS capabilities will not release.When judging about the value of data collection and interpretation, it is necessary to make sure that analytical measures are carry out and the reasons which affect human decision making are fully understood.Due to technological advance and social expectations from VTS functions, today its abilities have considerably changed and it has became a multidimensional means.The article trys to evaluate the background of elements that affect on human performance when working in VTS centers and a model will be introduced about how interactions take place. However, finally the aim is to find a solution to encounter elements that have counter effect on human performance.