According to the current status of the development of the hydrological data service, this paper analyzed the workflow of hydrological data service, studied the principles of workflow and workflow reference model, and designed a workflow model of hydrological data service with combination of the hydrological data index. We usedthe double-buffering technology, dynamic loading of hydrological data methods and AJAX technology, and finally designed a hydrological data automation service system that is highly efficient and reliable. The actual application of this system has achieved good results, which will solve the problem of the traditional way of processing hydrological data manually and provide a technical support for the modernization of hydrological data service.