Access authentication is the basic security requirement of hierarchical mobile IPv6 (HMIPv6) network. A mutual access authentication scheme is proposed in this paper based on hierarchical authentication framework as well as node certificate and identity-based hybrid approach. The scheme adopts identity-based cryptography to simplify the cumbersome key management of PKI. Node certificate is introduced to authenticate entity, which eliminates message interactions between home network and access network. A mutual authentication protocol is achieved using proposed hierarchical signature mechanism. The protocol can also be extended to support access authentication in multi-level HMIPv6 network. Performance and security analysis demonstrates that the proposed scheme outperforms other identity-based proposals in terms of efficiency and security.