Nano-scaled titanium oxide memristors exhibit unstable conductive characteristics under the same test condition: restricting the possibility to have accurate reading and control of the transient resistance of the device. Moreover, the reliability and stability of memristor-based circuits cannot be guaranteed. Coexistence of dopant drift and tunnel barrier is one of possible origins which causes undesirable instability, and the ambient temperature has a close relationship with dopant drift. However, there have been no detailed researches which may improve the stability of memristors by controlling temperatures. Based on the coexistence of dopant drift and tunnel barrier, the connections between temperature and memristor conductive characteristics are analyzed, and the influences of changes of active area width and initially doped layer width on the critical temperature are studied. Simulations are performed in SPICE and the results are given in this paper. In conclusion, methods are proposed for enhancing the conductive stability of memristors, which include increasing the active area width, decreasing the initially doped layer width, keeping the temperature to be under the critical value, and stability. Our work may provide a basis for manufacturing memristors with stable performance and promoting the practical circuit in applications.