Abstract: By methods of field trials and randomized blocks design, the effects of nitrogen fertilizer and density on physiological characteristics of precision hill-direct-seeding rice was studied in this experiment.The result indicated that different treatment of nitrogen fertilizer and density can change physiological characteristics significantly. Chlorophyll content，photosynthetic rate and plant absorbed nitrogen content was improved with the increasing amount of the nitrogen fertilizer increasing. Following aging，superoxide dismutase (SOD) activity decreased gradually，peroxidase (POD) activity firstly decreases and then increases，the content of malondialdehyde (MDA) firstly increases and then decreases.