Authentication test is a newly presented method that testifies protocols’ authentication properties. Its proving process is simple and precise; unfortunately it can not analyze protocols with test components multi-encrypted. This paper analyzes the authentication test scheme improved by Perrig and Song and points out its deficiency. Then it proposes an Enhanced Authentication Test theory and proves its soundness in formal. The enhanced authentication test lifts the restriction that test component can not be multi-encrypted in protocol messages, also repairs the inaccuracies in Perrig’s scheme.