A field plot experiment was conducted to investigate the effects of different combined application ratio of organic-inorganic fertilization on CH_4 and N_2O emissions in paddy season in a wheat-rice double cropping system by using the method of static chamber gas chromatographic-box techniques in 2015. The rice cultivar of Wuyunjing 29 was field-grown. Under the condition of equivalent nitrogen substitution, five treatments such as single chemical fertilization application (M1), and 25% organic fertilizer (M2), 50% organic fertilizer (M3), 75% organic fertilizer (M4), 100% organic fertilizer (M5) instead of chemical fertilizer were designed. And the greenhouse effect of CH_4 and N_2O emissions from paddy field was calculated by using global warming potentials (GWP). The results showed that: (1) the seasonal variation in CH_4 emissions was consistent in different treatments, but there was significant difference for CH_4 emissions amount, which was 203.37, 242.06, 255.04, 288.06, 334.46 kg·hm~(-2) from M1 to M5 treatments, respectively. The seasonal variations in N_2O emissions was consistent in different treatments, but there was significant difference for N_2O emissions amount, which was 3.96, 3.43, 3.27, 2.97, 2.60 kg·hm~(-2) from M1 to M5 treatments, respectively. (2) Turns of global warming potentials (GWP) of CH_4 and N_2O emissions was M5 > M4 > M3 > M2 > M1 in different treatments of rice season, and M5 treatment significantly increased GWP (9 136.8 kg·hm~(-2)). (3) Comparison with M1 treatment of single chemical fertilization application, organic fertilizer instead of chemical fertilizer increased greenhouse effect in rice field in the Taihu area. However, M3 treatment of 50% organic fertilizer instead of chemical fertilizer ensured rice yield, and the GWP of per unit rice yield was the lowest in different treatments, so it was a relatively suitable replacement ratio of organic fertilizer instead of chemical fertilizer.