Abstract: A Multiple-Input Multiple-Output(MIMO) radar system, unlike traditional phased-array radar, can transmit via its antennas multiple probing signals that are correlated or uncorrelated with each other, therefore can get higher performance. Deceptive jamming requires low power and can get vivid jamming effect, it is necessary to study how to remove effect of such kind of jamming. Orthogonal signals used by MIMO radar can make unnetted deceptive targets unable to focus, but when the Jamming-to-Signal Ratio is high, many flase alarm targets will exist. In order to remove those fake targets, one algorithm based on different cross ambiguity functions of different signal pairs is proposed. Multiple biphase coded signals that are orthogonal with each other are produced through genetic algorithm as signals transmitted, images of echoes of each kind of code is detected with constant false alarm. Through data fusion, targets in images of echoes of all different signals are fused, and are determined whether they are real targets or not, the effect of deceptive jamming on radar is removed completely. Anti-jamming efficiency is analyzed for MIMO radar under deceptive jamming. Simulation result testifies that the algorithm can help MIMO radar remove deceptive jamming completely produced by unnetted jammer, and is valuable for improving the anti-jamming efficiency of radar.