The ambiguity in tracking of Multiplexed Binary Offset Carrier (MBOC) modulated signals will severely degrade the tracking accuracy. Therefore, unambiguous tracking for MBOC is crucial prerequisite for modern Global Navigation Satellite System (GNSS) receivers. In this paper, a new unambiguous technique is proposed based on combined correlation functions for MBOC which are used in the Galileo E1 band and Chinese BeiDou II system. The mathematical derivation of autocorrelation function of MBOC and the cross-correlation function between MBOC and Pseudorandom Noise (PRN) conventionally used to overcome the tracking ambiguity is firstly given followed by the unambiguous receiving technique based on the Combined Correlation Function (CCF). The tracking performance of the proposed technique is analyzed and simulated. The simulation results show that the proposed method can solve the ambiguity problem thoroughly as well as enhance the multipath resistance capacity.