The purpose of this research was to investigate, with the strategy of cooperative learning and traditional narrative teaching, the learning achievement, scientific attitude, and the diversity of different class environment for the seventh graders¡¦ learning in biological reproduction of natural science. In addition, the progress of learning and teaching were studied followed up. In the quasi-experimental design, 27 subjects of the experimental group were taught by Student¡¦s Team Achievement Division (STAD) of cooperative learning, and 27 subjects of control group were by traditional narrative teaching. They were all seventh grade students in Kaohsiung County. The instruments consist of ¡§Biological Reproduction Learning Achievement Test,¡¨ ¡§Science Attitudes Scale,¡¨ ¡§What Is Happening in This Class? Questionnaire,¡¨and ¡§Cooperation Learning Questionnaire.¡¨ The data were analyzed by applying descriptive statistics and ANCOVA. The results of the research were summarized as follows: STAD cooperative learning teaching method stimulated students to show more positive scientific attitudes and experienced more class environment encouragement. Moreover, it promoted the seventh graders¡¦ learning achievement in study the unit of reproduction and exhibited retentive effect. During the different stages of group discussion, students were in a hopeless tangle in the beginning, followed by a more cooperative manner gradually, and finally they were leading group learning. The processes of the sharing of the groups were embarrassing in the beginning and then they were gradually open-handed at the end .Objectively, students think they could complete the learning of biology with cooperative learning and subjectively, they also enjoyed this kind of learning atmosphere and hope the teacher could use the teaching strategy of cooperative teaching more often. On the other hand, the teacher was able to follow up the students¡¦ thought and progress to guide them in more details during the group discussion and group sharing. Also the teacher should listen and respect the students¡¦ opinion and will even though the teacher worried about the methodology didn¡¦t suit for the students in the beginning.