Resistance switching (RS) devices that are based on titanium dioxide (TiO2) nanomaterials have recently attracted substantial research interest because of their simple preparation technology and potential applications in the applications of memory devices. In this paper, the RS characteristics of TiO2-based memristors were regulated by changing the crystal structure of the TiO2 film. Resistive switching memory, consisting of Ag/amorphous TiO2/Ti fabricated by anodic oxidation, exhibited poor cycling stability. Annealing was applied to the anodized sample over the temperature range of 230–680 °C, and the structure of TiO2 was investigated throughout the process. Amorphous TiO2 transformed into the anatase phase as the annealing temperature was increased to 280 °C and the stable cycle number of the device peaked at 51. By annealing at >450 °C, TiO2 was gradually transformed into the rutile phase, and the stable cycle number of the device decreased to 7. X-ray photoelectron spectroscopy confirmed that the concentration of oxygen vacancies in rutile TiO2 decreased with increasing temperature compared with that in anatase TiO2, resulting in the declining performance of the device. This work presents a low-cost annealing process to prepare stable anatase TiO2-based memristors, which will promote the industrialization of the devices for nonvolatile memory applications in the future.