Luliangyou 996(early rice) and Fengyuanyou 299(late rice) were selected for field experiment to investigate the planting parameters(water saving, density increasing and nitrogen reducing) effects on photosynthetic characteristics, yield correlation and water use efficiency of double cropping rice. Under the water-saving condition of “early storage and late irrigation”, conventional fertilizer density(CK) and normal density without nitrogen fertilizer(N0), densification and nitrogen reduction(IR1,IR2,IR3) were set up for this study. For early rice, the nitrogen application rates of IR1, IR2 and IR3 were 103.2, 86.4 and 69.6 kg/hm2, respectively, and the planting densities were 3.2×105, 3.6×105 and 4.0×105 plants/hm2, respectively. In late rice, the nitrogen application rates of IR1, IR2 and IR3 were 129, 108 and 87 kg/hm2, respectively. The planting densities were 2.8×105, 3.2×105 and 3.6×105 plants/hm2, respectively. The results showed that chlorophyll relative content(SPAD) of IR3 treatment was higher than that of other treatments at booting stage and full heading stage of the early and late rice. The net photosynthetic rate(Pn) at tillering stage was higher than that at milking stage, and the Pn of IR3 at booting and milking stage was higher than that of other treatments. There was a significant positive correlation between yield and SPAD in tillering, booting and full heading stage of early rice and booting and full heading stage of late rice. And, Gs and Ci at booting stage of early and late rice were significantly positively correlated with yield. Tr at tillering stage was significantly negatively correlated with yield. Compared with conventional fertilizer density treatment, densification and nitrogen reduction IR3 treatment could not only increase SPAD and Pn, but also significantly improve water use efficiency.