This article gives the spatial geometry model of bistatic radar Displaced Phase Center Antenna (DPCA) technique based on two-antenna. The bistatic radar DPCA technique requires that the distance between the two transmitting antenna phase centers (d), the pulse repetition interval (PRI) and the speed of the moving platform (Va) are strictly associated, just as the monostatic case. When the speed of the moving platform fluctuates, we can suppress clutter and detect moving target by interpolating and registering. The validity of the theoretic analysis is proved by simulation.