Due to the fast paced growth of world economy the energy demand is increasing very rapidly. To maintain the quality of power, economical production and long run performance of the plants should be kept failure free (as far as possible). So, these industries invest much more for up-gradation, high level of automation and use sophisticated machineries to get the desire level of results. But, still these industries are lagging in dependable and reliable supplies of electricity. Today most of the power plants are operating with low efficiency. In most of the cases it is less than 30%. There are a few plants in which efficiency is more than 60%. To prevent such mishaps a detailed system behavioral analysis along with maintenance planning is important. For which a mathematical model is necessary which exhibit the system upstate in quantitative form and analyze system performance in actual operating conditions. It is also helpful to process design department for modification in design and to maintenance department to in monitoring the system performance and planning in advance to keep system failure free for longer duration. The work presented here is mainly concerned with reliability centered maintenance of thermal power plant. The study is conducted in a Thermal Power Plant situated in Rajasthan.