The invention discloses a cross-trust-domain authentication method used for a distributed network system. According to the method, a distributed secrete key generation and threshold signature mechanism based on an elliptical curve cryptosystem is adopted to construct a virtual bridge authentication center (VBAC), and cross-domain interaction authentication between different trust domain entities in the distributed network system is completed through the VBAC. The cross-trust-domain authentication method has the advantages of being universally applicable to various organization structures, agile, dynamic, low in cost, short in authentication path, high in bit safety, high in efficiency and the like, in addition, the method can be realized by hardware easily, can easily solve the problem of cross-domain interaction authentication between the different trust domain entities of the dynamic distributed network system under the condition that terminal resources or the communication bandwidth is limited, and has wide application prospects in cloud computation, a cloud storage network, the internet of things, a wireless sensor network, an agile manufacturing system and a virtual organization.