For its good concealment ability and flexible station placement requirements, the passive tracking and location system by a single fixed observer receiving the signal transmitted by a moving emitter and measuring the Time Of Arrival(TOA) and Direction Of Arrival(DOA) has attracted widespread concern recently. As to the defects of unstability and poor precision of tracking algorithm using the difference of TOA and DOA, a new extended Kalman tracking method which uses the modulus operation by the known fixed repetition period of emitter signal and then combines the DOA information of emitter signal to locate the emitter is proposed. Simulation results show that this method can achieve the Cramér-Rao Lower Bound(CRLB) and high success location rate.