Embodiments of the present disclosure disclose a network roaming protection method and related device. The method includes: receiving, by a visited session management device, a first session establishment request that includes a first security requirement; obtaining, by the visited session management device, a target security policy, where the target security policy is obtained by processing the first security requirement set and a second security requirement set using a preset rule; and sending the target security policy to the UE instructing the UE to generate a target shared key based on a reference shared key and according to a rule defined by the target security policy, where the target shared key is used to protect secure end-to-end data transmission between the UE and the visited gateway.