This research aims to describe the level of discourse readability in the text book of Indonesian edition of revision 2017 class X on students of SMK NU and SMK Al-Falah Pati with cloze test. The textbook under study is an Indonesian textbook published by the Ministry of Education and Culture. The type of research is descriptive qualitative. The data in this research is the contents and score of the cloze test that has been done by the students according to the discourse in Indonesian text book. Data source in this research is cloze test which have been made from discourses contained in textbook. In the textbook the discourse that can be made population amounted to 20 discourse, while the sample is only 10 discourses. The researcher gives explanation in advance about how to do the test questions, then the students are asked to do about 35 minutes. After obtaining the data, the data will be analyzed using cloze test test. Based on the results of the analysis can be concluded that the level of legibility of textbooks of Indonesian edition revision 2017 for SMK class X entered in an independent category. Overall this textbook can be understood by the students and worthy of use as a teaching material
