Abstract: Aimed at the problem which takes advantage of Beidou Satellite Signal to test weak reflected signal within Non-cooperative Detection, this article comes up with the algorithm by utilizing the auxiliary of direct channel reflected channel to achieve signal acquisition. The article adds the auxiliary of direct channel information to the algorithm which combines with Short-term matched filtering-Fast Fourier Transform Algorithm(STMF-FFT) and Simplified Differentially Coherent Integration(SDCI) , in order to shorten the satellite search time,narrow the scope in two-dimension of frequency and code phase and improve the sensitivity of testing weak reflected signal and time of signal acquisition simultaneously. In the end, the simulations reveal that the acquisition sensitivity of this kind of algorithm can acquire the weak reflected signal power reduced to 151.3dBm and increased by 3.1dB compared with non-auxiliary algorithm.The average acquisition time shorts 39.5s.