Abstract: The zero values in BOC(1,1)(binary-offset-carrier) signal correlation function could make the receiver judge that the signal was not acquired. From the sub-carrier phase and code phase viewpoint, an acquisition method with three parallel tags was proposed to acquire the BOC(1,1) completely. The BOC(1,1) and its spread code correlation function figure were drawn by digital simulation, and the correlation function peaks were compared. The analytic formula for BOC(1,1) autocorrelation function was deduced, the position for peak values and zero values were shown. The correlation function values and acquisition were compared between BOC(1,1) and its spread code. The phase in one tag served as benchmark, the other two tags phases were respectively earlier or later than the benchmark in three local BOC(1,1) signals. The generation method for three local BOC(1,1) signals and the acquisition method figure were shown. When the difference of code phase between the received and the local BOC(1,1) signal lies in the half code chip, the signal acquisition rate increases from 33.3% to 100%,and the code phase range increases from 1/6 to 1/2 chip width by simulation. The method can provide phase information to the track loop and adapt to acquisition for BOC(n,n) signal.