Using the simulated rainfall methods,the affecting factors of soil infiltration are studied.The results show runoff time has a negative relationship with soil bulk,a ntecedent soil moisture,slope gradient, rainfall intensity, and different tillage measures;soil steady infiltration rates have a positive relationship with rainfall intensity and tillage measures,and have a negative relationship with soil bulk,antecedent soil moisture,and slope gradient.The major factors which affect soil steady infiltration rates and runoff time are soil physical property and tillage measures according to result of synthetic analysis.