A method for estimating the same frequency-adjacent cell channel of multiple cell united detection in TD-SCDMA system includes obtaining estimations of channel in local cell and channel in adjacent cell for obtaining an initial variable of local cell and for confirming a tap of adjacent cell, confirming position of one tap over said threshold in adjacent cell from taps at its existed window and position of code wheel in said window, judging whether there is data contribution corresponding to window position in initial variable or not and confirming whether said tap is out off window or not based on said judgment result.