Abstract: The point kinetic equation of reactor can reflect the change of neutron density in reactor core with time, but the traditional point reactor kinetic equation is not suitable for molten salt reactor. This is due to the fluidity of the fuel in the molten salt reactor and the delayed neutron precursors generated by the core as the flow of molten salt affects the core neutron balance. In this paper, the modified point kinetic equation is used to derive the analytical solution of the equation. The numerical method is used to verify the analytical solution. The results show that the analytical solution and the numerical solution are basically accordant. According to the analytic solution, the expression of the cycle of the molten salt reactor is deduced and validated by the numerical solution. The results of analytical solution and numerical solution are basically in agreement.