This study aimed to investigate the effect of the reading-writing-application method from cooperative learning on the understanding of environmental science. Intervention mixed method design was used. The quantitative part of the study was designed with pre- and post-test applied the quasi-experimental design. For the qualitative part of the study, writing reports of preservice science teachers were examined. 58 (31 experiment, 27 control group) third level preservice science teachers were enrolled in the study. To collect data, Environmental Achievement Test, the Scale of Cooperative Working Skills and group reports prepared by preservice teachers were used. The reliability and validity of the measurement tools were assessed, and the test and scale were finalized. In the study, the cooperative reading-writing-application method was found effective for learning environmental science course. According to the data obtained from the Scale of Cooperative Working Skills, there was no difference between the groups in pre- and post-views. According to the data obtained from the group reports, there was progress in writing skills of preservice science teachers.