The malicious behavior initiated by internal personnel will cause security threat to the enterprise, and there are difficulties in detection, such as fuzzy boundary, less sample data. This paper proposes an LSTM regression model, which outputs the prediction results of behavior sequence through regression analysis. Considering the otherness of variety users, the model learns the behavior mode of each user according to identify the user ID, and it is trained with updating sequence periodically, and then the difference between the predicted value and the actual value was taken as the abnormal score during test. This method can not only predict the users' behavior in next period, but also detect the abnormal behavior according to the normal behavior pattern learned, solving the problem of insufficient positive samples.