Remote Sensing satellite shall be provided with complex redundant functions owing to its high reliability requirement. However, for generating its corresponding reliability block diagrams come from understanding operational scenarios, dependencies between the electrical circuits in the system and following the circuit's characteristics. For a reliability block diagram contained redundant designs, normally the corresponding mathematical formulas of that reliability can be mapped accordingly. If no proper formula for that design can be used, the derivation of the fitting equations is necessary. In the reliability block diagram, most of the internal electrical parts have serial relationships. Hence, a grand total of the failure rates of the electrical parts can retrieve the failure rate in that block unit. Furthermore, to follow the reliability block diagram can evaluate the prediction of system reliability. This paper will describe the processes of reliability prediction in the Remote Sensing satellite system for referring in the future missions or predicting other complex systems.