[Objective] The aim was to explore effects of silicon at different concentrations on morphology and photosynthetic physiological mechanism of japonica rice. [Method] Seedlings of japonica rice were treated with silicon at different concentrations (0, 30, 80, 130 and 180 mg/L of sodium silicate); silicon contents were measured with Molybdenum blue spectrophotometric method in root, stem and leaf; plant height, root length and number in different treatment groups were measured with tools; chlorophyll a and b, and a/b in leaf and stem of rice in different groups were measured. [Result] Silicon contents in vegetative organs were as follows: stem〉leaf〉 root; when silicon was 80 mg/L, japonica ecotype was shortest; when silicon was 30 mg/L, root length of the rice was shortest and root number was least; when silicon was 30 mg/L, contents of chlorophyll a and b were highest and chlorophyll a/b achieved the peak when silicon was 80 mg/L. [Conclusion] Silicon at proper concen- tration would improve lodging-resistance and efficiency of photosynthesis, further enhancing yield of japonica rice.