Aiming at the difficulty to analyze the strength of car frame through theoretical calculation, the experimental analytical method is put forward. Static loading experiment is carried out under various working conditions. The necessary equipments of experiments as well as the test contents and the evaluation of the results are introduced respectively, and the stress and distortion of car frame under different loadings are analyzed. The suggestions of design and production are proposed. The results show that the design requirements of the strength of car frame can be met by strengthening the weak parts.