Abstract: To investigate the effect of different loading conditions (scratch speed and scratch distance) on the scratch behavior of polypropylene (PP) and polymethyl methacrylate (PMMA), scratch tests were carried out on the two polymer materials. The scratch resistance of the polymer materials was evaluated by the critical load at each stage and the change of temperature rise during the scratch process. The results show that different loading conditions have a significant effect on the scratch behavior of PP and PMMA. With the increase of scratch speed, the critical load at each stage and the maximum distance of periodic failure crack of PP and PMMA both decrease, the temperature change (temperature rise) amplitude of PP increases, and that of PMMA decreases at first and then increases. With the increase of scratch distance, the critical load at each stage of PP decreases, that of PMMA increases first and then decreases, and the temperature change amplitude of PP and PMMA both increases. The results have a certain guiding significance for the improvement of scratch resistance of polymer materials.