The so-called liability insurance means that the liability insurer shall be liable for compensation when the insured is liable to the third party in accordance with the law. "Means when a situation (or insurance accident) caused by the insured will result in the loss of property, insurance through the insurance payment, compensate the insured losses in whole or in part, the loss of property, by request third people and. Security company provides electronic equipment or facilities for maintenance and property safety monitoring system, its purpose is to deter theft, shorten the time, reduce the loss, not to prevent thieves’ invasion, but cannot ensure zero loss of property. Therefore, prior to the strengthening of product insurance, can use the least money to buy the most adequate policy, so that can compensate for or mitigate the loss caused by the accident and reduce the risk of business.