Abstract: Since the auto-correlation function of binary offset carrier (BOC) signal has multiple peaks, there is a false tracking problem in BOC signal. In order to solve this problem, a concept of sub cross-correlation function and an unambiguous tracking method based on combination of sub cross-correlation functions were proposed in this paper. By analyzing and comparing the sub-correlation functions, a correlation function with only a single correlation peak and the narrow correlation characteristics of BOC were created. Taking BOC (1, 1) and BOC (10, 5) as examples, simulation analysis was carried out. The results show the effectiveness of de-ambiguity. Compared with ASPeCT and BPSK-like, the proposed method can remove side peaks and maintain narrow correlation. The phase discrimination curve shows that, compared with BPSK-like for BOC (1, 1) and BOC (10, 5), the linear region slope gain of the proposed method is 5.2 dB and 7.2 dB, respectively. In the anti-multipath performance, compared to ASPeCT and BPSK-like, the multipath error of this method is least. In the anti-noise performance, compared with BPSK-like for BOC (1, 1) and BOC (10, 5) respectively, the code tracking error standard deviation of the method is reduced by 0.046 <i<T</i<c and 0.030 <i<T</i<c.