Cluster application management plays an important role in cluster systems. With more and more applications being settled on clusters, application management faces more and more challenging requirements. This paper introduces a service-based cluster application management system called AppManager. Different from traditional job management systems, AppManager has a service-based architecture. The components of a job management system are modularized and encapsulated into services. All these services are accessible within a cluster or outsides over Internet. Besides the basic functions of a traditional application management system, such as resource management, application schedule and control, AppManager implements many excellent features including supporting a wide variety of application types, platform flexibility, high system scalability, high availability assurance for application, scheduling algorithm extensibility and so on.