Stream scheduling algorithm used in video_on_demand (VOD) system can largely increase system service ability by eliminating the service latency and improving the system efficiency. In this paper, a novel stream schedule called PeriodPatch is proposed. On the basis of Patching, a PERIOD rule is introduced, so that multicast streams are created orderly and fewer multicast streams are needed for the true video_on_demand (TVOD) service. Furthermore, PeriodPatch schedule ensures that the system can provide near video_on_demand (NVOD) service with a predictive andacceptable latency to the client if resource are exhausted out. The simulation results show that PeriodPatch is more efficient than others, with respect to both system resource required for TVOD service and average client waiting time (service latency) for a fixed available resource. In conclusion, the PeriodPatch is an efficient and economical stream schedule for VOD system.