A storage system and a method for processing a data operation request are disclosed. The method is applied to a storage system that has a write once read many (WORM) function. In the method, after the storage system receives a data operation request, which is used to change data stored in the storage system, sent by an application server, the storage system acquires a time difference between a real-time clock (RTC) and a reference clock, wherein the RTC is configured to provide system time for the storage system, and the reference clock cannot be modified when the system is running. Then, the storage system determines whether the time difference is greater than an accumulated time precision error of the reference clock, and refuses to execute the data operation request when the time difference is greater than the accumulated time precision error.