To make the high performance weak signal detection algorithms further applying in the fields of synchronization, channel estimation, equalization for high-data-rate broadband mobile communication systems, algorithms of single-layer autocorrelation, multi-layer autocorrelation, discrete wavelet transform are comparatively studied for the application in weak signal detection in this paper. Modeling and simulation studies are performed. Simulation results show that algorithms of both single-layer autocorrelation and multi-layer autocorrelation can smooth noise and extract useful signal effectively without knowledge of prior information, algorithm of multi-layer autocorrelation has better performance than algorithm of single-layer autocorrelation, and algorithm of discrete wavelet transform has the worst performance.