Abstract: With large number of voltage sag sensitive equipment put into industrial production, the loss caused by voltage sag is becoming more and more serious, so it is urgent to reduce the risk of user's loss by reasonable and feasible risk management mechanism. Insurance is an effective risk management method that can transfer risk and disperse risk. Therefore, in order to reduce the user's risk, it is of great theoretical value and practical significance to study the implementation process and cost-effectiveness of the highly-feasible voltage sags insurance mechanism. At present, the voltage sag insurance mechanism is rarely studied, and there is a lack of study on the combination and implementation of voltage sags and insurance.In order to improve the feasibility of the insurance mechanism and meet the risk characteristics of voltage sags, this paper establishes a voltage sag insurance mechanism based on the special property insurance form of business interruption insurance(BII). The operational process of voltage sag insurance was designed. The premium and compensation model was established. The optimal insurance policy for users and the profits evaluation method for power supplier were proposed. Finally, the empirical analysis of six companies in a semiconductor park in Southwest China as an example shows that the proposed insurance mechanism can effectively transfer and disperse the voltage sag risk of user, and achieve a win-win situation for both the user and the power supplier.