The sealing performance of hydraulic support is very important in safe mine production. The sealing size deformation has a great influence on the sealing performance of hydraulic support. The aging experiment of hydraulic support ring was carried out, and the shape change data lip opening under different temperature conditions was obtained. The linear relationship between lip opening size change and its performance index was established by using one-dimensional regression analysis, and the performance index and prediction model of seal ring deformation were obtained, which could effectively calculate and predict the lip opening size change of hydraulic support.