The role of combat simulation as an essential part of mission planning has significantly increased in importance. Combat simulation is based on model and data, and the key step of it is the creation and development of military scenario. Web Service-based Visual Scenario Generation System developed scenario markup language with XML standard, used the GIS component MapX for scenario graphical display and edit, realized the input, output, mapping, merge, distribution, validation functions of scenario data. The system implemented an approach to reduce scenario data preparation time, and it is loosely coupled with other specific simulation systems, can rapidly reuse scenario data regardless of the data format' heterogeneity of C4ISR systems, combat simulations, and other scenario generation systems. The system can make the interoperability between different simulation systems more flexible.