The intelligent controlling system of intelligent building can apply Internet of Things (IoT) technologies for creating various controlling operations. The aim of this paper is the development of an intelligent monitoring system of intelligent building based on IoT. We introduce the working principle of the monitoring system, the hardware platform as well as its software collectivity frame. In addition, some key technologies for implement the monitoring system are described. The system can carry out various functions, such as fault detection, data processing, storage and alarming of the operating status parameters, querying history data, tracing real time instances by means of acquiring the operating status data from various testing sensors and the like. It also can record various types of operating parameters and send them to control platform by network. The system could effectively solve the problem of the monitoring and management of the operation tasks. Consequently it could greatly improve the efficiency of the management and controlling of the intelligent building.