Abstract: This paper proposes a model in order to solve the problem of Sonar System Battlefield Damage Assessment and Repair (SSBDAR) in battlefields. According to causal reasoning of sonar system for warships, a battlefield damage evaluation model is developed based on Bayesian networks and the related evaluation procedure is put forward, as well as the related algorithm for decision-making is presented. With this model, each repair site is evaluated and the uncertainty of damage information is determined. This can make the process of evaluation and repair more efficient, and can be an effective way to handle such problems in the sonar system of warsh ips.