The present invention provides a security protection system and method for preventing drag of a DNS. The security protection system comprises a network access control module, a DNS library file protection module, a strategy management module and a log recording module; wherein the network access control module only allows a valid user to access the DNS from a valid address, with valid equipment and in a valid mode; the DNS library file protection module prevents DNS library files from being deleted, moved, renamed and copied; the strategy management module performs valid definition; and the log recording module records operating records in which the DNS is queried through a network and operating records in which the DNS library files are deleted, moved, and copied. The system and the method of the present invention provide anti-drag security protection for a DNS system, and have the advantages of comprehensive protection, good expandability, high security, low system resource occupancy rate, and good user experience.