This paper deals with the reliability model set of three-state component. From the static viewpoint, there are two kinds of models: (1) success, degraded, failure; (2) success, failurel, failure 2. From the dynamic viewpoint, we can give the unified reliability model of three-state component with six parameters (λ₁λ₂λ₃μ₁μ₂μ₃) when the failure rate and the maintenance cate are constant. Moreover, we can compute the probabilities of three states at any time t.