Abstract: In order to provide a small size, low cost, flexible application, low frequency and high target-strength target simulator in hydro-acoustic testing, a bubble clouds simulator design method for active sonar experiments is described in this paper based on the strong scattering characteristics of the bubble clouds in water. An acoustic scattering model of the bubble clouds is developed based on the effective medium theory (EMT). Firstly, the bubble clouds are divided into cubic grids, and then the image processing method is used to obtain the size distribution function of the bubble clouds within the cubic grids and followed by using EMT to calculate the acoustic reflection coefficient in each cubic grid and the attenuation coefficient of the acoustic wave incident into the cubic grid. Finally, according to the acoustic superposition principle the backward scattering target strength of the simulator is calculated. The numerical analysis under different parameters shows that the target strength is higher when the bubble clouds size distribution function shows a gamma distribution; the target strength increases with decreasing the size distribution interval and increasing the porosity; the resonant frequency decreases with increasing the porosity. Combined with the bubble clouds porosity distribution model, a set of small size simulator design parameters with high target strength at low frequency is provided for reference of relevant designers.