A significant advantage of the distributed aperture coherence synthesizing radar is transmit receive full coherencesynthetic detection of the target, realizing the maximum utilization of energy. In order to achieve coherencesynthetic detection, the unit radar must follow certain baseline selection criteria. This article gives radar baseline selection criteria respectively from  four aspects, including echo correlation, signal coherence, target resolution and antenna array block. On this basis, it is concluded that the baseline calibration error will not affect the joint array beam direction, or the angle pointing error, through theoretical analysis and simulation verification. Finally, this article analyzes the influence of the array pointing error on the joint array antenna pattern and joint antenna gain. As the phase difference is introduced, the joint array antenna sidelobe is gradually raised with the increase of the array pointing error and the joint antenna gain is lost.