<p>The East Main Hall of Foguang Temple is an immensely precious Tang Dynasty wooden building in China. Therefore, great caution must be exercised in the timely restoration and disease prevention of the heritage building. High-precision monitoring is carried out for timely detection of abnormalities and analysis of causes, so that reasonable measures are adopted to reduce or eliminate the risks faced by the hall in a timely manner and achieve preventive protection. Based on the description and purpose of preventive protection, this paper introduces in detail the technical route of monitoring of the East Main Hall and the analysis results of some monitoring data under the concept of preventive protection.</p>