Abstract: With the popular application of the video digital technology, the storage bottleneck of the video service system is becoming increasingly serious. Based on the analysis of the I/O scheduling algorithm of RAID and the characteristics of the video data, a new parallel prefetching real-time dispatch method for video media service is designed. It forecasts the next batch of data requested by the host and fetches the data from the disks to the buffer in advance. At the same time, it optimizes the tasks dispatching, which enables the two tasks to be executed in parallel: the task of returning the requested data to the host and the task of prefetching data from disks. It is seen from the result by I/O meter that the new method improves the performance greatly.