Currently some complex grid applications developing often need orchestrate multiple diverse grid services into a workflow of tasks that can submit for executing on the grid environment. In this paper, we present CROWN FlowEngine—a GPEL-based grid workflow engine for executing grid workflow instances. Besides basic functions of a conventional BPEL4WSbased workflow engine, CROWN FlowEngine has many features including hierarchical processing mechanism, multiple types of task scheduling, transaction processing, etc, which are of paramount importance to supporting workflow instances using GPEL language. CROWN FlowEngine will be adopted and widely deployed in CROWN Grid environment to support a wide range of service grid applications integration. We conduct several experiments to evaluate the performance of CROWN FlowEngine, and the results of comparing our work with GWES are presented as well.