Summary: The repair rate of a repairable system, which is the parameter most related with repairmen in availability models, is usually assumed to be a constant. This limitation means the productivities of repairman are assumed to be the same and not changeable. Actually the repair rate is decided by the skills of repairmen but different repairman has different level of repair skills, and the efficiency of a repairman is affected by its psychological conditions and the management. Then two availability models of \(K\)-out-of-\(N\): \(G\) Systems are proposed. The first one considers the difference of repairmen’s psychological conditions to the repair rate. Then the stead-states’ probabilities of these models are given mathematically based on the birth and death process. These works would make models more practical and realistic, and they’re helpful to analyze and to allocate human resource.