A low-cost and facile two-step UV photolysis method was used to prepare the InGaZnO (IGZO) resistive switching films and micro-arrays. Using benzoylacetone (BzAc) as the complexing agent, we synthesized a unique IGZO solution sensitive to the UV light of 328 nm. We found that high-performance resistive switching IGZO amorphous films could be obtained by UV irradiation (325~365 nm) at room temperature (first step), and further exposure to deep UV light of 185 and 254 nm at 150 °C (second step). We found that the first and the second steps of the UV soaking play different roles in the formation process of amorphous IGZO films. Combined with the rinsing process, patterned IGZO micro-arrays acting as memristive units were also obtained using this two-step UV photolysis process. The IGZO micro-arrays with a high ratio of 104 of on-state and off-state resistance were obtained.