Through combining an experiment and a numerical simulation, a study was carried out on supersonic mixing layer with splitters of different geometric configurations, which is under the condition of Ma₁=1.5，Ma₂=2.5，T_0,1=300K，T_0,2=1200K，and matched pressure p₁=p₂=86kPa.In the experiment, it was discovered that the thickness of mixing layer in the flow field with splitters in which a cavity is mounted grows as the ratio of the length to the depth of the cavity becomes larger; Splitters with sawtooth trail show great effect of mixing enhancement and making the flow field highly unsteady. In the numerical study, it was demonstrated that the mixing-enhancement effect of splitters with cavity is due to the cavity shear layer’s reattachment to the trail of the splitter, and splitters with sawtooth trail due to induced large-scale streamwise vortexes. 