Aiming at the condition that the breakdown rate and the maintain rate of the new scout equipment is unknown, scout equipment credibility probability model based on compound Poisson process theories is established. Recount the notion of the compound Poisson process briefly, then analysis and emulate the scout equipment which the breakdown rate and the maintain rate of equipment is unknown. Result shows that the credibility probability model isn’t dependent on the system parameters, for this reason, it not only can complete the dynamic analyze to the system credibility, but also can predict unknown parameter of a certain equipment system credibility.