In metallurgical and mining applications, it is not easy to install speed sensors, so the speed of the lifting motor is usually obtained using a speed observer. To solve the instability problem of traditional speed observers in practical applications when the sampling period is reduced after discretization based on shift operators, a new type of speed observer for discrete-time systems is analyzed and designed. The speed observer introduces the Delta operator, which improves the problem of unstable observation data caused by high-frequency sampling in traditional speed observers. And by establishing a motor speed observation system through simulation, the correctness of the conclusion was verified.