The embodiment of the invention discloses a signal synchronization device and system. The device comprises an acquisition module, a determination module and a compensation module, wherein the acquisition module acquires a first synchronous receiving signal received by a first communication device and a second synchronous receiving signal received by a second communication device; the first communication device synchronously receives a first radar echo signal and the first synchronous receiving signal through a first delayer, and the second communication device synchronously receives a second radar echo signal and the second synchronous receiving signal through a second delayer; the determination module determines a compensation phase of the second synchronous receiving signal based on theacquired first synchronous receiving signal and second synchronous receiving signal; and the compensation module performs phase compensation on the second radar echo signal according to the compensation phase to obtain an after-compensation second radar echo signal. In this way, the first radar echo signal and the after-compensation second radar echo signal are in phase synchronization, imaging focusing and phase precision is improved, and therefore imaging quality is improved.