Abstract: According to three releasing approaches of fission gas after the cracking of the dispersion fuel particles, the releasing models of crack connection, bubble connection and atom diffusion were established respectively, resulting in the releasing model of fission gas based on the dispersion fuel particle cracking. The releasing amount of fission gas was calculated by this model. Results show that the releasing amount of fission gas is mainly attributed to the releasing approach of crack connection, and the increasing rate of releasing amount gradually increases with the burn-up. With the increase of annealing temperature, the releasing amount rapidly raises, while the increasing rate gradually decreases with the annealing time. The crack widths calculated from the releasing model of fission gas are consistent with the experimental data, which verify the releasing model of fission gas based on the dispersion fuel particle cracking.