The purpose of this study was to analyze the content of the Biology textbook of Eleventh Grade )1398(, in senior High school, Experimental Sciences, Based on William Romei’ s Method. The research method was descriptive and quantitative content analysis. Data were analyzed using descriptive statistics )frequency, percentage and mean( and calculation of conflict coefficient based on William Romeian formula. Based on the findings of the study, the coefficient of learner engagement in each of the sections: text, images, questions, and laboratory activities was 1, 35, 0, 37, 0, 08 and 0, 08, respectively. Also the coefficient of learner involvement in the textual part of the plant part of the book was 0, 12 and in the animal part of the book was 0, 08. The results indicate that the book is active in the questions section and inactive in the text, images, and laboratory sections. Also, the comparison between the content of the text of the animal section and the text of the plant section shows that in both sections, the text of the book is written inactive and the level of inactivity in animal topics is higher.