Woodblock printing is a special technique to carve reverse characters or patterns on woodblocks with cutting tools and to print with ink, paper and other materials. It is such an important stage in the printing history of China that extremely precious ancient books and archives were printed with this technique. Woodblocks are the most important physical witness of woodblock printing. At present, the number of existing woodblocks is very small, so it is necessary to research on their preservation. In due to the plant cellulose, hemicellulose, lignin, pectin in wood and carbon, animal glue and other substances in ink, it is prone to mould and pests. The diseases and printing materials of a series of Qing dynasty woodblocks were observed and analyzed with 3D digital microscope, Scanning Electron Microscopy Coupled energy Dispersive Spectroscopy（SEM-EDS）, Fourier Transform Infrared Spectroscopy（FTIR）, microscopic Raman spectroscopy（Raman）and Laser Particle Size Analyzer. It was found that the woodblocks were mainly damaged by moth and mold, and the printing ink was pine soot. According to the disease condition, epoxy ethane was used for insecticidal sterilization and the preventive protection methods of woodblocks were researched.