The crystal often cannot smoothly enter the body growth process from the shoulder growth process during crowning growth of Cz Silicon monocrystal growth due to the appearance of Broken Edge. To study the key characteristic parameters that affect Broken Edge, a method based on the Maximum Mutual Information(MIC) to identify the key characteristic parameters of the shoulder growth process of Cz-Si monocrystal growth were proposed. The correlation coefficients of the characteristic parameters to a Broken Edge problem each was calculated by the MIC method and the analytic hierarchy process (AHP). Then the first k terms were sequentially extracted in descending order until all feature parameters were used as input parameters for the Logistic Regression model to predict probability of Broken Edge. The results obtained show the accuracy of the model is the highest when the first 13 features of MIC extracted feature parameters were used as input parameters; and the MIC method is superior to the AHP method in prediction accuracy.