There are many industrial systems that may experience operating state switches between storage and usage throughout their whole life-cycle, and it has been proved that the operation switches have great influence on equipment's degradation process.However, the issue of remaining useful life estimation for such kind of systems is seldom founded in the literatures.In this paper, some key problems are systematically analyzed, such as the stochastic characteristics of the operation state switches, the lasting time of each state, and the difference in the degradation rates in each state.Particularly, a two-state Continuous-Time Markov Chain (CTMC) is presented to approximate the switches between the states of usage and storage.Then the CTMC is integrated into the random coefficient regression model to realize the remaining life estimation.A simulation experiment shows that the presented approach can effectively realize the system's remaining life estimation under the condition of the operation state switches.