According to the operation characteristics of the airdrop torpedo,three factors that have great effects on detection probability of the airdrop torpedo are studied in detail,including torpedo searching area,entry point dispersion and submarine dispersion.The interactions among the factors are also analyzed.Probability theory is used for constructing the analytical models of the detection probability respectively under accurate information source and fuzzy information source.The experimental results show that the calculation result of the analytical method is highly consistent with the result of the simulation method.