The space-time registration technology between the measurement sensors of the mobile LiDAR measurement system is the core technology of the entire system design, and the problem of time synchronization is particularly critical. Aiming at the problem of accurate time synchronization between the inertial navigation system and the LiDAR and panoramic camera, combined with the Beidou navigation grant time system, a method was proposed which designed a time synchronization device to provide space-time registration information for vehicle-mounted measurement platforms that integrate LiDAR, inertial navigation system, panoramic camera and other mapping sensors. The vehicle-based mobile measurement system with full independent intellectual property rights was taken as the research object. Through this measurement system the LiDAR point cloud data was collected. Using the designed time synchronization device, the prepared upper software were combined with Beidou satellite navigation system for accurate time synchronization. Finally, the accuracy of time synchronization reaches 0.1 ?滋s, which verifies the feasibility of the design method of time synchronization device.