The clearance flow influence law and mechanism of pressure tip winglets with different fusion heights and lengths are investigated by numerical simulation methods based on a compressor cascade to weaken compressor clearance leakage and improve cascade aerodynamic performance. The result demonstrates that the tip winglet can improve the spanwise pressure flow and narrow the tip separation range, thereby suppressing the intensity of the leakage vortex. The enhanced effect on the leakage vortex is more significant when the tip winglet's fusion length range can include the leakage vortex's initial position. In addition, narrower fusion heights and longer fusion lengths enhance the improvement effect. The tip winglet provides the most significant effect, reducing total pressure loss by 0.64% and leakage by 16.8% when the fusion height is 1% blade height and the length is the whole chord.