A network function service invocation method includes sending, by a first network function network element, a first request message to an authorization network element, wherein the first request message is used to request permission to invoke a first network function service provided by a second network function network element, performing, by the authorization network element, identity authentication on the first network function network element; generating, by the authorization network element, a token when determining that the identity authentication succeeds, wherein the token is used to indicate that the first network function network element has the permission to invoke the first network function service of the second network function network element, and sending, by the authorization network element, a token to the first network function network element.