Abstract: To clarify the optimum amount of nitrogen and phosphorus fertilizer in soybean fertilization in central Henan, a field trial was set up, including nitrogen level (0, 60, 120, 180 kg/hm2) and phosphorus level (0, 45, 90, 135 kg/hm2). The dry weight was determined in the key growth period of soybean, and the yield was measured in the harvest period. Partial productivity, agronomic efficiency and economic benefits were calculated. The results showed that soybean aboveground dry matter mass increased with the growth period. The yield with nitrogen application increased by 9.01%-11.86% compared with non-nitrogen application. The yield with phosphorus application increased by 2.8%-12.0% compared with non-phosphorus application. The yieldincreasing effect was the most obvious and the economic benefit was the highest when nitrogen fertilizer amount was 120 kg/hm2 and phosphate fertilizer amount was 90 kg/hm2. When the nitrogen fertilizer amount exceeded 120 kg/hm2, the aboveground dry matter mass and yield decreased. When the phosphate fertilizer amount exceeded 90 kg/hm2, the phosphorus fertilizer utilization rate and yield-increasing efficiency decreased. The results indicate that the yield and economic benefit are the best when the nitrogen fertilizer application amount is 120 kg/hm2 and the phosphate fertilizer is 90 kg/hm2.