Because most of the cultural heritages have special environment, the existing information technologies cannot be used in these areas. Moreover, traditional site protection technologies also cannot maximize the conservation and utilization of cultural relics. IOT is applied in many areas as a rising frontier information technique. It has huge potential to integrate with the conservation of cultural heritages. In this work, firstly is the situation of cultural heritage protection and the existing problems in the conservation of cultural sites is analyzed. The relationship between IOT and cultural heritage conservation is described. The work discusses specially three parts of IOT technology which consist the information collecting of the heritage and environment, the long distance transmission of detective data and the real-time analysis of the data. Additionally, the work describes the relevant key technology of application solution. The applied cultural heritage conservation and utilization system – the IOT – based Dunhyang Magao Grottoes conservation and utilization system were introduced simply. The system accumulates a large number of monitoring data through successive years and makes an important contribution to the conservation of Mogao Grottoes. With further development of IOT, the application of heritage conservation will become deeper and wider, and this will further improve the efficiency of heritage conservation.