Abstract: This paper analyses the characteristics of splash noise and hydrodynamic noise produced by a high speed body moving into water and discusses the properties of the received timing signal in the background of these two kinds of noise mentioned above.The timing signal is emitted from a sound source carried by the moving body.The general principle of choosing the parameters such as the power of the source and the threshold level of the receiver is expounded.Finally,under assumed conditions the numerical values of these two parameters are estimated.