Academic honesty is one of character education that must be teached to our students integratedly in learning process. Bibliotherapy, especially developmental bibliotherapy is one of technics to teach values integrated in curriculum. This research aims is to find out the efectiveness of classrooom developmental bibliotherapy in Bahasa Indonesia learning to improve student's academic honesty. The type of this research is Quasi Experimental Reseacrh using Non Equivalent Control group Posttest Only Design. This research take 63 subjects on 4 th MI (Islamic Ememntary School) students. This research take two groups, devided into experimental and control groups. The treatment, CDB in learning was given to experimental group in four sessions. CDB is given integratedly in Bahasa Indonesia Learning with four steps: pre-reading, guided-reading, post-reading disscussion, and reinforcement/ problem solving. The measurement of academic honesty is using The Academic Honesty Schale, wich measure academic honesty in three aspecs; attitude, tendency and behavior. The test result through t-test shows that the data is significantly difference. It indicate that there is difference of cheating behavior on experiment group and control group. It means that there is influence of role playing method in learning to cheathing behavior on students.