Abstract: Considering application of long time accumulation to the detection and parameter estimation of linear frequency modulated continuous wave (LFMCW) signal, a novel method based on the joint inter-frame correlation method and cyclostationary method is proposed to detect LFMCW signal and estimate its parameters. Firstly, signal detection and exact period estimation is realized by inter-frame correlation method. And then, cyclostationary method is utilized to finish the phase parameters estimation of LFMCW signal. The algorithm realizes long time accumulation with low computational complexity and solves the problem brought by initial time-offset. On the low signal-to-noise ratio (SNR) condition, this method still has better estimation performance. Simulations verify the effectiveness of the method.