Abstract: There is water leakage at the left and right sides of the lower part of an automobile trunk sealing strip. In the present work, the common influencing factors such as the location of water leakage, the size of sheet metal, the structure and performance of the sealing strip, and the rolling process were analyzed, and the influence of the rolling speed of the rolling gun on the pullout force of the sealing strip was emphatically analyzed. The results are as follows. The pullout force of the seal strip at the thickness change position of the sheet metal was simulated and tested. It is found that with the increase of the rolling speed of the rolling gun, the pullout force decreases from 106 N/100 mm to 87 N/100 mm. The section where the sheet metal thickness increases from 4.5 mm to 5.8 mm at the location of water leakage was analyzed, and it is found that there is about 2.27 mm gap between the roller and sheet metal, which needs to be filled with non-setting adhesive and sealing strip, so as to avoid water leakage. By adjusting the rolling speed of the roller of the rolling gun from 720 r/min to 460 r/min and strictly controlling the sheet metal thickness at different positions, the water leakage problem of the trunk sealing strip can be solved, which provides technical support for the analysis and solution of subsequent similar problems.