The localization accuracy of traditional radio frequency identification (RFID) indoor localization methods is low. To address this issue, a RFID indoor localization method based on dual-frequency carrier phase is proposed. Frequency hopping technology is employed to obtain rough range estimation with virtual large bandwidth to achieve multipath suppression. The selection of the optimal dual-frequency points is completed based on multipath suppression. The particle filter localization algorithm is designed by using the optimal dual-frequency point carrier phase. The resampling method in traditional particle filter is optimized by genetic algorithm, which effectively solves the problem of particle degradation and improves the localization accuracy. Experimental results show that the median localization error of the proposed algorithm is 5. 23 cm, which achieves 39% improvement than the traditional localization method based on Chinese remainder theorem.