Recently, grid computing environment has being changed to the service-oriented grid integrated with Web Services for supporting more open, scalable and flexible grid architecture. In this architecture, a grid application is the service-oriented grid application in which Grid Services are executed according to the workflow of the grid application. This implies that the grid scheduling method needs to consider grid service characteristics. Although many grid scheduling methods have been developed, we need new grid scheduling method to reflect the service-oriented grid concept and to ensure performance of the grid application. Therefore, we propose the grid service performance model based on factors such as service availability, accessibility, reliability, throughput, and slowdown, and develop grid scheduling method to increase performance of the service-oriented grid application.