This paper designs a cross-platform data interaction and information fusion mechanism for national security-oriented public security intelligence. The data interaction mechanism enables automatic cross-platform data invocation and cross-platform contract invocation. Subsequently, the encrypted communication protocol and security constraint algorithm for public security intelligence data are designed. Then the information fusion method based on information grid is designed. Simulation experiments show that the data interaction and information fusion mechanism proposed in this paper can accurately realize the adaptive scheduling of public security intelligence cross-platform, with a high information recall rate and a good checking accuracy rate. It improves the level of cross-platform data interaction and sharing of public security intelligence and intelligent management capability.