The traditional multipath mitigation algorithms for high-order BOC (binary offset carrier) signals have a narrow effective convergence region, which is a weakness for stably tracking, therefore, a multi-region discriminator for multipath mitigation of high-order BOC signals was proposed. The optimized QStrobe discriminator was applied when code error was in the near zero region, which improved the multipath mitigation performance, while the QBOC discriminator was applied in the other regions which had an excellent convergence performance. The Kalman filter was utilized to estimate the tracking error with open-loop method for real-time switch of discriminator. Simulation Results of BOC(15, 2.5) and BOC(14, 2) signals show that the multi-region discriminator algorithm can eliminate the tracking ambiguity. In addition, compared with the traditional QStrobe algorithm, the 6 dB attenuated multipath error envelope area is improved by 51% and 57% respectively.