The invention discloses a reducing crown sheave walking-beam-free oil pumping unit, which mainly comprises a small belt, a base, a supporting pull rod, a rope hanger, a frame, a big belt and a reducing crown sheave. A crank is arranged on the output shaft of a reduction box, a crank counterweight is arranged on the crank, the other end of the crank is sequentially connected with a connecting rod and one end of the small belt, the other end of the small belt is arranged on a small radius wheel of the reducing crown sheave, one end of the big belt is arranged on a big radius wheel of the reducing crown sheave, the other end of the big belt is connected with the rope hanger, the frame is arranged on the base, the reducing crown sheave is arranged at the top of the frame, one end of the supporting pull rod is connected with the upper part of the frame, the other end of the supporting pull rod is connected with the base, the reduction box and a driving motor are arranged on the base, and a transmission belt is arranged on the reduction box and the driving motor. The oil pumping unit has the characteristics of simplicity in structure, removal of a walking beam, simplification of a transmission system, high system efficiency, remarkable energy-saving effect, no need of moving the frame by equipment, fastness and convenience in well repair operation and the like, and is widely applied in oil extraction engineering of petroleum exploitation engineering.