An oil pumping unit is disclosed to include a motor, which has a mover that moves alternately up and down when the motor is electrically connected, and a pump, which has a barrel, an oil suction pipe mounted in the barrel, an inner sleeve, which is connected to the suction pipe and has installed therein a mixing valve, a movable valve and a piston, a bottom one-way oil intake valve, and a one-way mixing flow intake valve respectively arranged in such a manner that when the mover is operated to reciprocate the oil suction pipe, crude oil is alternately pumped through the one-way bottom oil intake valve and the one-way mixing flow intake valve to alternately pass through the movable valve and the mixing valve to the ground.