Acidification is an important factor affecting the documents preservation lifetime.This paper takes the deacidification patent texts as the research object. Subject recognition and clustering and frequency analysis are used to analyze the technical elements and practical research. The patents are mainly divided into three categories: deacidification solvent, method and equipment. Nearly 87% of deacidification technology invention are aqueous treatments. The main goals of deacidification technology invention are uniformity, safety, environmental protection, simple process and no influence on paper and handwriting. Nearly 30% of patents do not include practical research, which were invented only for a purpose of achieving a certain function. Most patents do not have comprehensive safety tests, and the safety measurement methods and the results expressed in patents are also different. So it is difficult to objectively assess whether a deacidification technology is safe and usable.