The disclosure provides an anchor authenticator relocation method and system. The method includes: after an old authenticator accepts an anchor authenticator relocation request of a Mobile Station (MS), a new authenticator sends an authenticator relocation request to an AAA server; when the AAA server's verification on the new authenticator is passed and the old authenticator confirms that the new authenticator is trusted, the anchor authenticator is relocated to the new authenticator. The disclosure provides a detailed solution to perform anchor authenticator relocation without re-authentication.