With the continuous expansion of business in meteorological system, the performance, stability, and maintenance efficiency of original core network have been short of capacity to meet the demand. To guarantee reliable and efficient operation of meteorological network system, current status of the network has been studied and rebuild demands are proposed, network reform schemes and equipment changeover procedures have been designed in detail, a new generation of CSS and iStack switch stacks technologies have been adopted in smoothly upgrading the meteorological core network based on network virtualization and visual fusion operation and maintenance platform, overall built a 2 layer flat meteorological network system. By rebuilding, the network structure is simplified, and the network performance and maintenance efficiency are improved.