The invention relates to a planet differential starter, used in the oil field pump. It comprises an output axle, a belt wheel, a bank, and a planet element. It is characterized in that: the bank comprises a transmission device, a planet device, a clutch device and a control device. Said transmission device comprises a gear axial sleeve, a output axle, a bearing, a sliding support, a inner tooth ring, a transmission hub and guide bolt. Said control device comprises a control axle, a handle, a connecting block, a support post, a revolving ring and a brake claw. Said clutch device comprises a spring core axle, a spring base, a spring and a compressing ring. And the planet device comprises a planet wheel support, a planet wheel, a claw wheel, and a planet wheel axle. The invention uses differential start, therefore, the motor with small power can be used, and it can save electricity, cost and non-working power consumption, with easy maintenance and long service life.