Abstract: Based on the theoretical calculation model, the manufacturing parameters related to the performance of fuel rods are obtained. With the help of FUPAC fuel rod performance analysis software, the sensitivity analysis of the parameters is carried out one by one, and the key parameters affecting the performance of fuel rods are selected. Based on a large number of calculation data of sensitivity analysis, the relationship function between the key parameters and the fuel rod performance is obtained by numerical fitting method, and the rapid and accurate evaluation of the effect of the manufacturing parameters of the pellet on the fuel rod performance is realized. The conclusion is that the numerical fitting method can effectively analyze the effect of fuel pellet manufacturing parameters on fuel rod performance through comparing the results of numerical fitting method and professional software analysis.