The invention discloses an outdoor LED projection lamp with a waterproof function, and relates to the field of projection lamps. The outdoor LED projection lamp comprises a base, a first supporting rack, a second supporting rack and a power supply connector, the power supply connector is formed in the surface of the base, a control keyboard is arranged on the side of the power supply connector, acontrol main engine is arranged on the bottom face in the base, a motor base is arranged on the side of the control main engine, a stepper motor is arranged on the motor base, and a rotation shaft isarranged at the end of the stepper motor. The LED projection lamp is provided with a sealed waterproof structure formed by a waterproof lampshade and a light focusing lampshade so that it can be guaranteed that water is prevented from entering the LED projection light during outdoor working, and thus the usage safety of the LED projection lamp is guaranteed. Meanwhile, a user can control the stepper motor to drive the first supporting rack to automatically adjust the projection angle in the horizontal direction through the control keyboard, traditional manual adjusting is replaced, and the user operates the LED projection lamp conveniently.