The invention provides a chain block external power device and a chain block system. The chain block external power device comprises a main chain plate, four auxiliary chain plates, a support installed on the main chain plate, a motor installed on the main chain plate, and a controller used for controlling the rotation direction and the rotation speed of the motor. The support is in an X shape and comprises a first end, a second end, a third end and a fourth end, wherein the first end, the second end, the third end and the fourth end are arranged in the circumferential direction of the main chain plate and protrude to the outer side of the main chain plate; the first end, the second end, the third end and the fourth end are each provided with one auxiliary chain plate; an installation joint used for installing a chain block chain is formed between each of the four auxiliary chain plates and the main chain plate. By the adoption of the technical scheme, the chain block external power device and the chain block system are simple in structure, low in cost, durable, portable, wide in application range, high in hoisting weight, high in efficiency, safe, convenient to install and easy to maintain.