Abstract: PSK-Like tracking method is widely used for its lower complicity and better hereditability. The BPSK-Like method regards the side-band of BOC signal as an ideal BPSK signal which will be inaccurate especially for anti-multipath purpose. An analysis of the side-band autocorrelation function was derived and an approximate analytical expression to describe the shape change was given out. At last a suggestion is developed for the selection of earlylate space which adapts for different bandwidth.