In order to let the Satcom-on-the-move (SOTM) users know the communication status of the current driving road in advance and avoid the blindness of the information transmission, a model of formulating SOTM satellite-switching strategy based on probabilistic visibility and breadth-first search is established. Firstly, through adapting JANUS visibility algorithm, a probabilistic visibility model based on terrain description error and interpolation algorithm is proposed to quantitatively represent the communication status of each road point on the whole road. Then, the breadth-first search algorithm is used to obtain the satellite- switching strategy on the condition of different satellite-switching time, and the appropriate satellite-switching strategy is selected for the user according to their requirements. Finally, the validity and practicability of the model are verified by an example.