The mural paintings in the Main Hall of Fengguo Temple are exquisite and unique, with immense historic value and artistic value. However, over time, the murals have suffered from various degrees of damage. One prominent issue is the presence of different types of attachments on the mural surfaces. A condition assessment of the current state of the four types of attachments on the mural surface reveals variations in their distribution. X-ray diffraction and infrared spectrometer are used to analyze the composition of four types of attachments. The results indicate that the four types of attachments are calcium carbonate, unsaturated polyester lacquer, paper fiber, and polyvinyl alcohol formaldehyde and polyvinyl acetate. Environmental monitoring and comprehensive analysis of relevant historic documentation suggest that the main cause of these attachments is closely related to historic conservation. The objective of this study is to systematically reveal the characteristics of the attachments covering the mural surfaces in Fengguo Temple through diagnostic investigation, component analysis, and causation analysis. This research aims to provide a theoretical foundation for the cleaning of the attachments and the conservation of the mural paintings.