In this paper an improved method is raised for ship wake detection with SAR images based on localized radon transform. The difference between this technique and traditional Radon transform method is that two local SAR images but not one which is usually used in the troditional way are used to process the Radon transform respectively. Then the result which the data in one image at Radon Space subtracted from the other processes the absolute operation. Only after all of steps above the choise of threshold and inverse Radon transform should execute. So, in this way, to select the proper threshold becomes very easy and the diagonal effect becomes weak. In addition, this measure can detect not only the bright line but also dark one at the same time. At last, from the result of applying this method to both simulation data and SAR data we conlude that it has better ability to find ship wake from the SAR image.