The purposes of this study are to examine the structure of factors that affect elementary science achievement in China and Japan, and to propose some strategies for elementary science education reform in China. The study hypothesized that science achievement was influenced by seven factors: (1)parental support, (2)classroom environment, (3)attitude toward science leaning, (4)peer environment, (5)study hour, (6)parents' interests in science, (7) parents' expectations in science teaching. The study revealed that the instrument had some validity in the measurement of each construct variable. In addition, the analysis in the Structural Equation Modeling indicated that the effects of positive attitude toward science study and class environment were influential factors to science achievement in Japan. On the other hand, in China, the effect of positive attitude toward science teaching is the only influential factor to science achievement.