Multicarrier signals have broad distribution in frequency domain, so the problem of low estimation accuracy for time difference of arrival (TDOA) and frequency difference of arrival (FDOA) of single carrier signal can be overcome through coherent integration to improve the efficient bandwidth. Focusing on the problem of multi-carrier signals detection and localization, the TDOA/FDOA estimation algorithm based on multi-carrier signals cross ambiguity function (CAF) coherent integration is researched, and a high accuracy location parameters estimation method for multi-carrier signals passive location is provided. Based on the received signal model, the CAF of each multi-carrier signal is deduced, and the phase relationship of each CAF is analyzed through TDOA and FDOA dimensions. Coherent integration is realized by phase compensation and the performance improvements of TDOA/FDOA estimation are analyzed in theory. Monte-Carlo simulations validate that the accuracy of the proposed TDOA/FDOA estimation algorithm based on multi-carrier signals coherent integration exceeds that of the single carrier signal obviously, and the performance improvements are the same as the theory analysis.