In this paper, we describe TIGRIS Grid MPI Service, which is 4he WS-Resource Framework (WSRF) based services to enable an MPI job to be executed on Grid environments. It covers heterogeneous compute resources and diverse MPI libraries. The main functionalities are as follows. First, it allows an MPI user to seamlessly launch a job without knowing how to use the specific MPI library. Secondly, it executes an MPI job on the cross-site resources by supporting the Grid-enabled MPI library such as MPICH-G2. Thirdly, it enables the user to launch a job using the source code without compiling. The service is implemented on top of the services of Globus Toolkit. We provide the user interface as a web portal and CLI(Command Line Interface).