Due to the influences of atomic clock and classical radio signal measurement accuracy, Loran C system is difficult to provide high-precision timing for users. In this paper, a microwave-optical entangled timing scheme used in Loran C system is proposed. The entangled microwave-optical signal is firstly prepared by the electro-opto-mechanical converter, then the signal propagation time is obtained by the second-order coherence function of the entangled signal, and finally the local clock time for users is corrected based on the timing sequence relationship and the timing is realized. The influence of electro-opto-mechanical converter parameters on timing accuracy is simulated and analyzed. The proposed scheme theoretically improves the timing accuracy of Loran C system, and has certain advantages in resisting suppression interference and deception interference.