Abstract: Inverse kinetic method can be used for reactivity real time measurement and has special advantage for components reactivity scale, reactivity disturbance measurement and transient analysis on power reactor. In this paper, the reactivity measurement system with inverse kinetic method on fast neutron critical facility was developed, and arithmetic validation and performance analysis of this system were implemented. The results indicate that this system has high precision, fast response, high resolution and can be used conveniently. It is proved that this system can satisfy experiment requirements.