The present paper deals with the study of the solar thermal power plant with the help of Markov process by the consideration of different failure and repairable facilities. A probabilistic model of the system has been developed through considering some assumptions. Authors have considered three types of failures such as equipment failure, non-availability of fluid and environmental failure. The present system under the study, consists of three possible states: good, degraded (partially failed) and completely failed state. Using supplementary variable technique and Markov process, a successful attempt has been made to evaluate the probability of each state and various important performance measures. Finally; some numerical examples and graphically representation are shown at the end.