A vehicle power generation system for a vehicle, the vehicle comprising an engine that supplies power to the vehicle, the engine comprises a crankshaft and a vehicle transmission unit connected to and driven by the crankshaft, and the vehicle transmission unit is connected to wheels of the vehicle, the vehicle power generation system comprising: a power generation unit, including a generator, a power input shaft driving the generator to generate power, and a power output unit electrically connected to the generator; a power supply unit, connected to the power output unit, and provides a power connecting interface; characterized in a clutch mechanism, including a speed increasing unit connected to the power input shaft, and a motor controller for attaching the speed increasing unit to the crankshaft or detaching the speed increasing unit from the crankshaft; a control unit, electrically connected to the motor controller, and including a power generation condition determining unit for determining whether the vehicle is under a safe and stationary condition that is suitable for power generation, and adapted to drive the clutch mechanism based on the result; wherein, the control unit is adapted to, after receiving a power generating mode switching signal to confirm that the vehicle is under a condition suitable for power generation, drive the clutch mechanism to attach to the crankshaft of the engine, thereby allowing the crankshaft to be connected to the power input shaft of the generator, and the control unit is adapted to increase a rotation speed of the engine to a first setting rotation speed value, and then to increase the rotation speed of the engine even more to a second setting rotation speed value through the speed increasing unit, thus the generator is driven and electrical power for the power supply unit is hence generated; wherein, the control unit is adapted to, after receiving a vehicle-moving mode switching signal, drive the clutch mechanism to detach from the crankshaft, thereby ending power generation. a power generation unit, including a generator, a power input shaft driving the generator to generate power, and a power output unit electrically connected to the generator; a power supply unit, connected to the power output unit, and provides a power connecting interface; characterized in a clutch mechanism, including a speed increasing unit connected to the power input shaft, and a motor controller for attaching the speed increasing unit to the crankshaft or detaching the speed increasing unit from the crankshaft; a control unit, electrically connected to the motor controller, and including a power generation condition determining unit for determining whether the vehicle is under a safe and stationary condition that is suitable for power generation, and adapted to drive the clutch mechanism based on the result; wherein, the control unit is adapted to, after receiving a power generating mode switching signal to confirm that the vehicle is under a condition suitable for power generation, drive the clutch mechanism to attach to the crankshaft of the engine, thereby allowing the crankshaft to be connected to the power input shaft of the generator, and the control unit is adapted to increase a rotation speed of the engine to a first setting rotation speed value, and then to increase the rotation speed of the engine even more to a second setting rotation speed value through the speed increasing unit, thus the generator is driven and electrical power for the power supply unit is hence generated; wherein, the control unit is adapted to, after receiving a vehicle-moving mode switching signal, drive the clutch mechanism to detach from the crankshaft, thereby ending power generation.