With the popularity of cloud computing, more and more business are operated in the cloud computing. In this paper, we address the problem of service request scheduling in cloud computing systems. We consider the three-tier cloud structure, which consists of resource providers, service providers and consumers. The service request scheduling strategies in this scenario should satisfy the objectives of the service providers and consumers. We propose a new strategy dynamic priority scheduling algorithm (DPSA) to solve this problem. The algorithm is more efficient and optimal than the FCFS and SPSA. © 2011 IEEE.