The invention provides a communication message security interaction method and a device of a distribution automation system. After completing two-way identity authentication between a distribution master station and a distribution terminal, a main distribution station obtains distribution terminal information from the distribution terminal. The main distribution station judges whether that distribution terminal is the first identity authentication according to the version number of the symmetrical key of the distribution terminal, if not, the message exchange between the distribution terminaland the main distribution station is carried out; otherwise, after the symmetric key of the distribution terminal is updated, message exchange between the distribution terminal and the distribution master station is performed. The scheme makes up for the shortcomings that the distribution master station can not identify the distribution terminal in the distribution automation system security protection system, and the confidentiality and integrity of the communication message can not be guaranteed, and improves the security protection level of the vertical communication between the distribution master station and the distribution terminal in the distribution automation system. At that same time, the problem that the remote control/parameter set message has the hidden trouble of the replayattack and the like are sol.