In order to understand the influence of water content on the dynamic characteristics of oil-water emulsion, firstly the pressure wave velocity formula of the oil-water emulsion in the pipe is deduced in the body to establish the nonlinear relationship between water content and the frequency characteristics of emulsion transmission, and to analyze the law of effect of water content on the emulsion transmission speed. Then the parameters of distribution theory and transfer matrix method are used to develop the transmission frequency model of water in oil emulsions. The results show that oil-water emulsion propagation speed decreases with the increase of water content, considering fluid solid coupling effect of PVC transparent steel wire hose; on the contrary, with water content increasing, the transmission speed of emulsion is increasing trend in steel pipe. It′s obvious that the influence of water content on resonant frequency of the oil-water emulsion transmission system, is higher with water content rate in emulsion, and the same order of the resonant frequency of the system is lower. Further, with the resonant frequency of the order is greater under the increase of water content, the difference is corresponding bigger than the same order of the resonant frequency. The effectiveness of the model is validated by the experiments, to provide theoretical basis for water content detection in oil and guarantee the safe operation of the system