Aluminum alloy surface exists naturally occurring oxide film, which is prone to defects such as porosity in the aluminum alloy body welding process. Laser cleaning is an effective method to remove aluminum alloy oxide film. This study investigates the energy density window for nanosecond pulsed laser cleaning of aluminum alloy oxide films by examining the physical and chemical behaviors of oxide film removal under pulsed laser action. The laser with a maximum average power of 100 W was used for laser cleaning. The physical and chemical behaviors of vaporization and thermal vibration peeling during the process were studied by a high-definition camera system. Surface morphology and oxygen mass fraction after laser cleaning were also studied. A numerical model was established to verify the observed physical and chemical behaviors. The average power vaporization and melting thresholds were derived. As the energy density increases, the thermal vibrational peeling phenomenon gradually becomes more intense. The oxide film removal mechanism changes from melting and vaporization to thermal vibrational peeling mechanism. The optimal process window for oxide film removal is 18 J/cm²~30 J/cm², and the effective removal of aluminum alloy oxide film can be achieved by laser cleaning within the window.