Abstract: From the sealing mechanism of the sealing element, a geometric dimension measuring system of the seal was established based on a 3D image measuri ng instrument. The geometric dimension measurement was conducted on the bud-shaped sealing element.The accuracy and repeatability of the inspection method was verified.Meanwhile based on the sealing performance test of sealing element, the finite element simulation was applied to analyze the theoretical study on several typic al sealing elements and the relative conclusion was obtained.In combination with the above geometric dimension measuring means, sealing performances test and the「 elative theoretical analysis, a sealing performance evaluation system of the sealing element was set up for the sealing element of the hydraulic cylinder applied to the h ydraulic powered support and thus the sealing quality of the hydraulic powered support could be effectively improved and the hydraulic leakage of the hydraulic jack co uld be reduced.