Recently, the lead-free double perovskite Cs 2 AgBiBr 6 has been considered as a promising candidate for next-generation nonvolatile memory and artificial synapse devices due to its high stability and low toxicity compared to its lead-based counterparts. In this work, we developed a simple and effective method to produce high-quality lead-free double perovskite Cs 2 AgBiBr 6 thin films without pinholes and particles by applying a low-pressure assisted method under ambient condition with a relative humidity (RH) of about 45%. The formation of pinholes and Ag precipitation in the perovskite Cs 2 AgBiBr6 films is effectively suppressed by the proper ratio of N,N-dimenthylformamide (DMF) mixed in dimethyl sulfoxide (DMSO) solvents. Furthermore, the grain size of the Cs 2 AgBiBr 6 films can be significantly increased by increasing the post-annealing temperature. Finally, a sandwiched structure memristor with an ITO/Cs 2 AgBiBr 6 /Ta configuration was successfully demonstrated, featuring ultralow operation voltage ( V Set ∼ 57 ± 23 mV, V Reset ∼ -692 ± 68 mV) and satisfactory memory window (the ratio of R HRS / R LRS ∼ 10 times), which makes it suitable for low-power consumption information storage devices.