Dimensional analysis on parameters of wheel-soil interaction system was performed, and the parameters’ scales were also acquired when the density and cohesion of simulant regolith were kept consistent, respectively. The lightweight model method was adopted to eliminate the influence of low gravity environment, and a 1/2 scale lunar rover model was designed. The slope angle and wheel velocity were taken as the experimental factors, the wheel sinkage and slip ratio were taken as the experimental index, test on lunar rover’s slope trafficability was carried out, and the experimental factors’ influences on the wheel sinkage and slip ratio were analyzed. Variation laws of the driving torque, drawbar pull and traction coefficient with the slip ratio under different slope conditions were analyzed. Results indicated that the influence of slope angle on trafficability was more obvious than that of wheel velocity. With the increase of slip ratio, the driving torque and drawbar pull presented increasing trend, and the maximum values of the driving torque and drawbar pull were up to 3.6N·m and 10.5N, respectively. The traction coefficient was increased first and then decreased with the increase of slip ratio, and it was up to its maximum value of 0.18 when the slip ratio was 21.6%. In order to ensure that the lunar rover had safe and reliable trafficability, the exploring slope angle within 20° was reasonable. The research result would provide a reference for the evaluation of lunar rover’s slope trafficability under low gravity environment.