The purpose of this study was to investigate the effect of science journal writing on science-related attitude and science academic achievement of elementary school students in order to find out the value of science journal writing. For this purpose, one class of 6th graders was tested. The result of this study were as follows: First, Science journal are classfied by forms and content. The most frequently used types are prose and organizing concept. Second, Science journal writing brought positive effects on science - related attitude, especially cognition of science. Third, Science journal writing has positive effect on science academic achievement. Therefore Science Journal Writing can be useful method in Science education.