Abstract: A dynamic fitting method for the actual efficiency of crane lifting motors based on operating current is proposed to address the problems of insufficient accuracy and poor real-time performance of existing methods in measuring motor efficiency under dynamic working conditions. The party constructed a dual layer architecture of "dynamic efficiency reference model+current driven fitting model", using wavelet packet multi-scale analysis to extract current dynamic features, combined with a comprehensive loss real-time compensation mechanism, to establish a nonlinear rational function fitting model with dynamic correction. The experimental results show that the efficiency fitting goodness determination coefficient R² of the method proposed in this paper reaches 0.974, and the efficiency estimation error in the rated load area is small.