Reducing the viscosity of heavy oil is of great significance in petroleum production and transportation. In this paper, we studied the reduction of viscosity of crude oil under the irradiation of a 532 nm laser in which the variation of current, temperature, and viscosity was also studied and discussed. Owing to the photolysis-product absorption and order-n multiphoton absorption, both the current and temperature increased over time with the laser turned on, simultaneously, leading to the breakage of chemical bonds and the drop in viscosity. With its advantage of rapidness, collimation, and no contact, laser technology may serve as a powerful tool to reduce the viscosity of crude oil.