The photosynthetic characteristics of Citrus microcarpa were determined with the Li-6400 Photosynthetic system.The results showed that the diurnal variation of net photosynthetic rate (Pn) in Citrus microcarpa was a double-peak curve and there also exists a clear depression at noon.The first peak occurred at 11:00,the second one at 14:00.The maximum of net photosynthetic rate (P_max) was 3.4467 μmol/m²·s.Correlation analysis showed that there were positive relationship between Pn and transpiration rate (Tr) and stomatal conductance (Gs),and negative relationship between Pn and internal CO₂ concentration (Ci).Under the concentration of CO₂ 400 μmol/mol,the light compensation point (LCP) of Citrus microcarpa was 67 μmol/m²·s,and light saturation point (LSP) was 672 μmol/m²·s.In sum,Citrus microcarpa is a typical masculine and shade-resistant plant which has strong adaptability to the circumstance.