The preservation principle of questionnaires should ensure the integrity, security and convenience of information files. Specific measures include: ① Arrange a certain space, purchase necessary facilities and equipment for keeping files, and ensure that these archived files can be protected against theft, sun, high temperature, fire, moisture, dust, rats and insects. (2) Designate full-time management personnel; ③ When placing paper documents such as questionnaires; Considering the ease of use, for example, it can be placed by number, and a catalog card is established to reserve room for expansion.