Abstract: An identity-based cross-domain authentication protocol is given out, which is among domains in large-scale distributed collaborative computing network. It adopts bilinear mapping and short signature technology to achieve mutual authentication between entities in different domains, and can overcome the complexity of certificate transmission and bottlenecks in the scheme of PKI-based. The analogue and analysis show that this scheme has anonymity, security and can support mutual anonymous authentication, and it is applied to the security alliance authentication mechanism in large distributed network.