Attestation is one of the critical problems to Trusted Computing.The solution project of attestation in TCG,due to bad extensibility,inflexibility,bad performance and leaking privacy,is becoming bottleneck to application,popularizing of Trusted Computing.In this paper,the formal concept of attestation is defined,functional structure and execution mechanism of the ternary and the quadruple attestation system are presented,and pointed out that the attestation of identity is a “push” quadruple attestation system,and the attestation of platform is still ternary attestation system,Moreover,the development about Attestation of Identity,Attestation of Platform and Attestation of Runtime Environment,and so on,are analyzed.This paper also presents a summary of the current state of these techniques,a discussion on the future research topics,and the challenges of attestation of TCG.