Abstract: In order to realize a trusted private network,firstly,trusted computing technologies are utilized. Then with the use of combined public key algorithm(CPK),the trust chain from trustworthy terminal can be led into private networks,and the USB Key technique is used to overcome the weakness of CPK.Finally, with the cryptogram management and security management as the center,a comprehensive secure defensive system is constructed,and a trusted network model is established to realize security,authenticity,controllability and reliability of private networks.