As a new radar technology, the distributed aperture coherent radar would be the next generation radar, which is more easily to transport and less expensive than the traditional large aperture radar. However, the time synchronization and phase synchronization are the key issues for the distributed aperture coherent radar. In the paper, the error sources of time synchronization and phase synchronization are analyzed and the corresponding mathematical models are derived firstly. And then, the impact of synchronization errors on the coherent performance is simulated and the accuracy of time and phase synchronization is presented based on the simulation results. At last, the noncorrelation transmission scheme and the calibration scheme based on the wired transmission are respectively proposed to realize the time synchronization and the phase synchronization. The research on the synchronization problem could be very helpful to realize the new radar technology of distributed aperture coherent radar.