Abstract: This study aims to investigate the rules of drip irrigation on soil water content and yield formation of summer soybean, and provide references for high yield and water saving of optimal drip irrigation amount of summer soybean.【Methods】A field experiment under drip irrigation with five amounts of drip irrigation: 3780 m3/hm2(W1), 3360 m3/hm2(W2), 2940 m3/hm2(W3), 2520 m3/hm2(W4), and 2100 m3/hm2(W5) were set in a randomized block experimental design in 2016. 【Results】 The results showed that with the increase of drip irrigation, the water content in 0-60 cm soil layer increased. The soil water content of 0-40 cm soil layer changed little at different growth stages, while it changed greatly in 40-60 cm soil layer. The plant height and stem diameter of soybean in the whole growth period followed the sequence: W2>W1>W3>W4>W5. Leaf area index (LAI) and leaf area duration(LAD) initially increased and then decreased with increasing irrigation volume, all treatments reached the maximum at the seed filling stage. W2 treatment was the highest in both LAI and LAD, which was 5.66 and 97.83 m2?d, respectively. Moreover, the maximum increase rate of dry matter(Vm) , the total dry matter accumulation and yield were also highest in W2 treatment, and the yield of W2 was 3133.25 kg/hm2, which increased by 8.08%, 11.48%, 27.87% and 47.73% in comparing with that of W1, W3, W4 and W5. The irrigation water use efficiency had no significant difference among treatment W2, W3 and W4. However, there were significant differences between W1 treatment and other treatments (P<0.05).【Conclusion】Based on comprehensive analysis on growth and development, yield and irrigation water use efficiency of summer soybean, it proposed that the appropriate drip irrigation quota under mulch film for high yield and water saving of summer soybean should be 3360 m3/hm2.