Intelligent building in construction projects in the proportion increased year by year. But in the construction project, is the most simple system integration project has only BA performance, fundamentally not intelligent building. What is the difference between the weak current system, system integration, intelligent building of the three? System integration in a broad sense can be considered intelligent building? A thorough distinction on the above concept, to determine the function of different investment according to the actual benefits, but also to ensure that the project in the weak electronic system and intelligent function to achieve the intended purpose, which requires investors and users of the three positioning project were analyzed carefully.