In this paper, the optimal switching and condition based maintenance decision of a cold standby switching system with random shocks is studied. Firstly, an off-line condition based maintenance strategy with periodic switching and inspection is proposed, based on the analysis of the structure and maintenance characteristics of the switched operation system. Secondly, the reliability models of competitive failure, between soft failure caused by system degradation subject to cumulative shock process and hard failure caused by extreme shock process, are established. Then, the iterative model of probability distribution of system state at each inspection point is derived by analyzing the characteristics of state transition in the process of alternate use and maintenance of operation and standby equipment subject to two kinds of shock processes. Furthermore, an analytical decision model is established to minimize the average cost rate to obtain the optimal switching period and maintenance threshold. Finally, the effectiveness of the strategy and the model are verified by taking the coal mine main ventilator system as the example, and the sensitivity of the model to the parameters is analyzed. The results show that the optimal maintenance strategy of the system changes significantly with the impact of shocks.