Abstract: The definition of three-valued equation models of society diagnosis（that is equation description of three-valued models of society diagnosis） is first set up.Owing to the characteristics that traditional two-valued model of society diagnosis can’t be without “t-diagnosable”and absolutely distinguishes human beings into two （good man and bad man）.A kind of new society diag-nosable model is set up，the concepts of “t/x-diagnosable”etc.are defined.Finally a concrete method—equation diagnosis algorithm is found，on seeking all consistent fault patterns for the three-valued society diagnosis model.

摘要： 首次建立起三值社会诊断方程模型的定义（即三值社会诊断模型的方程描述）。针对传统的二值社会诊断模型离不开“t-可诊断性”和绝对区分人类为两种（一种好人，一种坏人）的特点，建立一种新的社会诊断模型，并根据此模型，引入“t/x可诊断性”等概念，并在此基础上，找到了求三值社会诊断模型相容故障模式的具体方法——方程诊断算法。