Abstract: The computer simulation has very important significance for reactor operation and training operators. Based on Simulink, the characteristics of pointreactor neutron kinetics equation with sixgroups delayed neutron were researched when a step reactivity was inserted in the reactor with temperature and poison feedback. Main parameters of a certain reactor were calculated under two typical operating conditions with positive and negative step reactivity. The results were compared with those obtained by 3D simulation software of reactor. It is shown that the system requirement can meet efficiently and rapidly with Simulink.