Textbooks play an important role in shaping the national identity of students. The purpose of this research is to examine and analyze the national identity in the mathematical book (1) of the 10th grade of the secondary school. The method of research is quantitative and qualitative content analysis. The information gathering tool includes a checklist in content analysis, and the analytical unit is themed. The dimensions of national identity in this research are the symbol, value, cultural heritage, celebrities and characters, events and happenings. The statistical population of the mathematical library (1) is the 10th grade of the secondary school (mathematics and physics and experimental sciences) in 1396-1395. The results of the qualitative analysis show the emphasis on national values, attention to places and buildings in the cultural heritage, and the low use of hadiths, verses, literary order, and the lack of attention to economic values and contemporary celebrities. According to the results of the quantitative analysis, 132 references to the concept of national identity are mentioned in this book. Among the dimensions of national identity, the dimension of national values with 42. 31% of the highest frequency of events and happenings with 0/76% have the lowest frequency.