Abstract: Web service selection based on quality of service (QoS) has been one of research focuses in service computing field. Current methods of service selection usually focus on a single service request or multiple service requests for co-selecting a shared service at a time, not considering the competitiveness among multiple independent service requests for the same functional Web services. A global optimal service selection model for multiple service requests, according to the matching degree (between service requests and Web services) and 0-1 integral programming, is proposed to solve the conflicts among service requests. A universal and feasible optimal service selection algorithm, named global optimal service selection for multiple requests (GOSSMR), is proposed to solve the model. Under the condition of meeting QoS requirements of service requests, too many requests selecting the same Web service at the same time can be avoided, thereby optimizing the service resources, avoiding the overload, and improving the performance of the system. The feasibility and effectiveness of the model and algorithm are verified by simulations in our work.