Abstract: Memristor is a passive electronic device with a non-volatile memory,which is proposed by Leon Chua in 1971.A 2-terminal non-volatile memory device based on resistance switching was found in HP labs in 2008,and that proved the existing of memristor.In this paper we analyze two modeling methods of memristor and then design an improved model of memristor based on the physical model of memristor that found by HP labs.It can be found that the characteristics of the improved model correspond to the physical model of HP labs by PSPICE simulation.