Abstract: This paper took double cropping system of winter wheat-summer maize in semi-humid area as the study object. Three treatments including conventional tillage (T0), no-tillage without mulching (T1) and notillage with mulching (T2) were conducted to study the effect of tillage and straw mulching on soil water content and temperature and crop growth and the effect in different crop seasons was also studied. The results showed that the soil water contents in 0-60 cm soil layer of T2 and T1 treatment were higher than that of T0 treatment, and the topsoil water contents of T1 and T2 treatment had significant difference, which indicated that straw mulching had obvious effect on soil water retention in topsoil. No-tillage with mulching reduced soil surface temperature (T2＜T1＜T0), but the effects in different crop seasons were different: top soil temperature of T2 and T1 treatment had no significant difference in winter wheat seedling stage, but it was significantly different in summer maize seedling stage and influenced germination, but the emergence rate had no significant difference. Different from the results in semi-arid and semi-humid area, no-tillage with mulching reduced winter wheat yield, the main reasons were the reduction of emergence rate (8.7% in 2013 and 13.3% in 2014) and spike number of per hectare (3.8% in 2013 and 5.0% in 2014). For summer maize, straw mulching had yield-increasing effect (17.2%), the main reason was the increase of kernels per spike (11.5%). No-tillage with straw mulching could conserve soil water content and decrease topsoil temperature of double cropping system of winter wheat- summer maize in semi-humid area, but the effect in different crop seasons were different, and those effects were not the main influencing factors of crop yield.