In order to investigate the response characteristics of soil infiltration on different boulder outcropping slopes to rainfall in karst area,the influence of four boulder outcropping conditions and five rain intensities on infiltration was studied. Field artificial rainfall simulation method was adopted. The results showed that: (1) When the rainfall intensity was 30 mm/h,the size of the boulder outcropping rate had no significant effect on infiltration. However,in the other rainfall intensities,the rate of boulder outcropping was 5.4%,which had little effect on infiltration; while the rate of boulder outcropping was 13.1%,which inhibited infiltration,and the rate of boulder outcropping was 42.9%,which promoted infiltration. In the early period of rainfall,the existence of boulder could promote the infiltration. (2) When the boulder outcropping rate and rainfall remained unchanged,the stronger the rain,the less the infiltration. While the average infiltration rate increased first,then decreased and then increased again. In the early period of rainfall,with the increases of rainfall intensities,the infiltration volume decreased first and then increased. And the early infiltration rate increased with the increases of rain intensities. In both cases,the inflection point occurred when the rain intensity was 90 mm/h. (3) After simulating the infiltration process,it was found that universal empirical model showed better fitting effect than Kostiakov model on the boulder outcropping slope.