Focusing on the nature of complexity and uncertainty of coal enterprise's employee turnover risk, the combination weight and unascertained measurement(UM) estimation model are established. On the basis of using AHM-entropy to determine the weight of risk factor, the method of unascertained measurement is applied to analyze different forms of human resource in coal enterprise, each risk level is obtained. Finally, the estimation approach is validated by an example, also providing the suggestions to enterprise's risk management.