Abstract: In order to predict the behavior of the fuel rod in reactor, mechanisms and experiment observations of many physical phenomena need to be combined to establish proper calculation models. China Nuclear Power Technology Research Institute Co. Ltd. (CNPRI) recently developed a fuel rod performance analysis code named FRIPAC, which considers the combined effects of physics, chemistry, materials, thermodynamics, irradiation, etc. on the performance of fuel rods during operation. Thus, FRIPAC can predict fuel behavior in reactors reasonably. The physical model of FRIPAC was briefly introduced in this article. The assessment was made based on experimental data. The results show that the prediction of FRIPAC on fuel central temperature and fission gas release is in good agreement with the measured data, which verifies the correctness of the FRIPAC model. For the future work, the FRIPAC is expected to continue with the assessment of internal rod void volume, cladding corrosion, etc. and to continuously optimize the models based on the assessment results.