A field rainfall simulation experiment was carried out to assess the impacts of conservation tillage on run off and infilt ration, and the effects of surface tillage, residue cover and wheel traffic compaction were also studied. The results showed that conservation tillage, which features more residue cover and less soil disturbance,could remarkably delay and reduce runoff and improve infiltrati n compared to conventional moldboard plough practice (CK) . Under the experimental situation with lowantecedent soil moisture and 72 mm/h of simulated rainfall rate, CK could produce runoff 12～16 minutes earlier, and the final infiltration rate could be 60. 9% lower and total runoff could be 11 times more than conservation tillage. Among the three factors, residue cover is more efficient for reducing runoff and increasing infiltration. Wheel traffic compaction also has considerable impact and could increase runof f by 4. 5 times; while the effect of surface tillage is not great. Conservation tillage combined with less traffic compaction can be an effective option to control run off from loess farmland.