There are a large number of books in the library, and the temperature and humidity conditions affect the preservation life of books. The temperature and humidity field inspection instrument can monitor the temperature and humidity in various areas of the library. Setting up monitoring points in different areas such as densely packed bookshelves areas and borrowing areas can obtain comprehensive temperature and humidity data. A humid environment is easy to cause paper to mildew and stick together, and high temperatures may accelerate paper aging. The inspection instrument helps the library staff to timely regulate the environmental temperature and humidity, and use means such as ventilation and dehumidification to protect books from damage and provide better reading resource protection for readers.