The fractional Fourier transform (FRFT) is a generalization of the Fourier transform. To the linear frequency modulation (LFM) signal, the FRFT is a good way for signal accumulation. Aiming at the linear frequency modulation characteristic of the anti-radiation missile (ARM) echo signal, an improved method for ARM detection based on FRFT is proposed. The areas of peak search were reduced and the detection efficiency was improved when the FRFT was localized. The simulation experiments show that the reliable detection of ARM signal can be achieved with this method under the Gauss or non-Gauss clutter environment.