Abstract: The traditional computer cluster is not easy for management. For example, it is hard to install the systems, lack of secure isolation of different users; it cannot construct the customized environment according to the requirement of applications and users etc. Virtual machines can be used to tackle all these problems. A system called TDDS(task deployment and dispatch system) based on virtual machines has been designed and implemented. TDDS can build up the running environment according to the requirement from users and applications. In addition, TDDS builds the automatic application deployment and schedule system as well as load balancing among physical servers in the cluster. The main contribution of this dissertation includes:1) Two different virtual machine setup methods are proposed for speeding up the application deployment based on customized virtual machines. 2) The task deployment and schedule mechanism are designed and implemented based on the virtual machines. TDDS can construct the virtual environment for distributed applications and schedule the tasks on the virtual platform.3) Several experiments have been conducted to test the effectiveness and efficiency of computing environment and resources customized for user applications. The experiments indicate that TDDS can do the task deployment and scheduling efficiently. The load balancing schemes can be used to improve the processing capability of physical clusters i.e. achieving the goal of improving the usage efficiency.