In view of the waste of energy in using air-conditioner, a smart air-conditioner control system was put forward and implemented in this study. This system, which is based on OneNET, monitors temperature and humiture in real time and controlls the air-conditioner remotely by a smart air-conditioner control device module. It includes mobile phone app, virtual devices on OneNET, and a smart air-conditioner control device module, which can be applied to various brands of air-conditioners. The smart air-conditioner control device module based on STM32 collects temperature and humiture in real time and transmits data to OneNET. Users could check data by mobile phone app and transmits instructions to the smart air-conditioner control device module by OneNET. The smart air-conditioner control device module communicates with air-conditioner by infrared. The results show that this system could monitor temperature and humiture in real time and air-conditioner could be used economically, which creates a comfortable living and working environment.