Radar target recognition is an important aspect of modern radar technology. With the development of radar technology at higher levels and better functions，it is necessary to set up an advanced automatic target recognition system in air-defence. In this paper，according to aircraft's fast and flexible features，a new recognition approach is proposed by using Mellin transform and bispectrum estimation to obtain radar targets' signatures. The nearest-neighbour (NN) alogrithm can be used for classification of radar targets The results of computer stimulation tests show that this approach has better noise proof ability and higher recognition rate.