Workflow mechanism is used into grid system to combine multiple grid services to implement complex grid application. But the workflow is not programmable, and is not flexible enough for users as well. In this paper, a Distributed Programmable Grid System (DPGS) is put forward. In DPGS, a course-grained parallel programming interface GridPPI is implemented. Through it, user could couple multiple web services in DPGS to completed complicated requests. Based on Globus Toolkit 3.9.3, the DPGS provides a simply organized, extendable and scalable grid environment for grid designer to design and deploy traditional or new applications.