Abstract: By using APSIM model, the effect of precipitation seasonal distribution on crop yield was determined in rain-fed agriculture area of the Loess Plateau. Next, the effect of precipitation seasonality on crop yield was explored via integral regression analysis. The study shows that APSIM model can reliably simulate wheat and pea yield. Crop yield is highly related with annual precipitation and its seasonal distributon. The seasonal distribution of participation has a positive U-shaped quadratic relation with wheat and pea yield. Precipitation in the months of June and July significantly influences wheat yield, while that in the months of May and June importantly influences pea yield. With 1 mm increase in precipitation, wheat and pea yield respectively increases at the rate of 10.4 kg·hm^-2 and 10.3 kg·hm^-2. Seasonal precipitation distribution more importantly influences crop yield than annual precipitation.