Abstract: From the mechanics and the control requirements of the scraper conveyor, a view between the soft start and load balance coupling control of the scraper conveyor was provided and a contral diagram was provided.According to the requirements of the control method, the Sigmoid function mode of the liquid coupling featur es under the varied liquid flling quantity was provided.Based on the circumstances, the local and full linearization was conducted on the liquid coupling model and the li nearization model of the liquid coupling was obtained.The model could directly applied to the analysis on the control system performances of the scraper conveyor.