Abstract: The dynamic nature of grid environment brings some new characteristics to grid workflow, which increases the uncertainty and complexity of the working flow. A norm-driven grid workflow state machine model named GridWSM is offered, which utilizes norm to describe the dynamic scheduling of the tasks in the grid workflow systems. Its advantages are that the norm can express different semantics exactly and is competent for depicting complicated systems. The ratiocinative ability of the norm can validate and perfect the description of norms about grid workflow systems, check the semantic conflicts among the norms, ensure the completeness of the description of norms and reflect the dynamic changes of the working flow. GridWSM can also picture real-time states of grid workflow systems, which will be the theoretical foundation for the emulation of systems. Finally, the prototype system named NormTools validates the norm description of grid sorting flow, and finds all errors.