Field plot trial was conducted to study the effects of organic manure and inorganic fertilizer combination on photosynthesis characteristics and activities of nitrate reductase (NR) and sucrose phosphate synthetase (SPS) in rice functional Leaves, by applying different combination of organic fertilizer (straw, pig manure, pig manure composting or biogas fertilizer) and inorganic fertilizer. Results showed that combination of pig manure composting and chemical fertilizer showed more advantages than the other organic fertilizers, which embodied in improving the net photosynthesis rate and enzyme activities of nitrate reductase and sucrose phosphate synthase in rice flag leaves, ensuring stable grain yield and rice quality. Compared with pure chemical fertilizer treatment, the enzyme activities of NR in early rice flag leaves at booting stage improved by 65.06%, and enzyme activities of SPS in early rice flag leaves at ripening stage improved by 7.70%, grain yield increased by 19.65%, and contents of free amino acid in rice increased by 43.87 mg/kg in the treatment applied the combination of 20% pig manure composting and 80% chemical fertilizer.