Abstract: Based on the analysis of the problems in current multi-vendor network management system NBI(north-bound interface) model，the UIP (unified interface platform) was proposed and used in China Telecom WDM network management system. UIP can resolve the difference and incompleteness of NBI developed by different vendors with different models through the unified interface model, which can also reduce the difficulty and cost of development in system upgrading and maintenance. By using UIP, WDM network manangement system, configurated in different circumstances， needn’t develop many interfaces for different vendors and EMS versions. The new network can be monitored as quick as possible, and the time of removing the fault and costs of software development and maintenance can also be reduced.