In response to the smart noise jamming under multi-channel broadband digital radio frequency memory repeater jammer, an orthogonal decomposition method for anti-jamming was put forward on basis of chaotic modulation signals and multiharmonic phase modulation chirp signals. Both of these two signals have a ″thumbtack″ ambiguity function. They are not only of good resolving power in range and Doppler, but also of good sensitivity to echo frequency. By an orthogonal and diverse design, they can better adapt to the smart noise jamming under multi-channel broadband digital radio frequency memory repeater jammer. The result of analysis and validation on the anti-jamming performance of the new method through computer simulation shows that under smart noise jamming in multi-channel broadband digital radio frequency memory jammer, the electronic counter-countermeasures improvement factor of the new method can be more than 10 dB, which is much better than that of the traditional frequency and slope agility method.