In recent years， parameters real-time identification based on dominant parameters selection has become a promising way to improve efficiency of composite load identification. The existing ways to select dominant parameters are mainly based on sensitivity analysis. However， they are usually depending on different basic parameters set， disturbance or system operation situation， and it is difficult to reflect mutual influence among the parameters. Based on mechanism analysis， a strategy to analyze the relationship between independent parameters set and redundant parameters set is presented. Then， according to the implicit characteristics of induction motor， a simplified model with proper accuracy is also presented， based on which the number of dominant parameters can be further reduced. The simulation results verify the accuracy of presented strategy.