The scientification and informatization evolution of power grid planning and programming management put forward higher requirements to the flexibility, efficiency and security of the system's design structure. Because of this, this paper proposed the development method of planning and programming information management platform for national grid based on three-tier B/S architecture. On the basis of analysising the three-tier B/S architecture's features, three layers consist of client representation layer, application logic layer and data layer of the system were designed and implemented with the SoTower tools. The rich client technology was used to develop client side of the system. WebLogic and Oracle were used as the application server and database server respectively. The final system has functional integrity, and high grade performance. This system has tested running in pilot(experimental) units now, and got a good application effect.