A new sampled data processing method of switch antenna is proposed for space-time spectrum estimate in switch antenna array system. This method constructs the switch antenna array’s particular array manifold matrix and steering vector which contains channel switch interval and sampling interval. It dispenses with pretreatment to original data so that they can apply to the existing spectrum estimate algorithm directly. Based on this data processing method, distortionless space-time planar array algorithm and irredundant L-shaped array spectrum estimate algorithm in switch antenna array are given. With smaller hardware scale, the two algorithms which avoid signal distortion are more closed to multi-receiver array algorithm in performance; the latter one’s computational complexity is also lower through the comparison of algorithm cost among the classical algorithms and the proposed algorithms. Simulation analysis verifies that the two algorithms are effective.