With the application of the geostationary satellites, the problem how to prediction the in-orbit life of the satellites is taken into account, especially the satellites with liquid propellant. The methods of propellant measurement and management have been studied by many people, and the assignment and the end-of-life prediction is thought to be a necessary work in satellite engineering. This paper discusses the factors that may influence the in-orbit life of geostationary satellite, such as space environment, capability of the equipment, the wasting fuel and the ground operation. The propellant mass is proved to be the main factor in engineering. The end-of-life prediction accuracy analysis should be based on the on-board sensor accuracies and satellite telemetry processing accuracies. The methods of how to measure and estimate the propellant-remaining of the Chinese satellite are given as PVT method, BookKeeping （BK） method, and combined method （PVT＋BK）. The prediction methods of the satellite give the average life, the reliable life and the actual life. The engineering example shows the predication method based on propellant-remaining is reasonable.