Through analyzing the principles of Hu variant moment and affine variant moment，it has been known that the character of invariant moment would be unchanged when the image is moving，flexing or turning.Combining this principle，and based on a great deal of field experimental data，the characteristics of ship infrared image were analyzed.Then the turning ship has been recognizably studied according to Hu and affine invariant moments.From the quantity of data got in the test，it was found that the turning ship can be recognized finely.