Abstract: The highlight structure model of underwater target echo and the model of underwater target dimension recognition based on cross-spectrum method of splitting beam are given. The generating methods of reflecting and scattering highlights digital time series are presented. We introduce a method to simulate the target scale characteristic with a circular arc array placed in an anechoic pool. Each projector of the arc array transmits acoustic highlight simulating signals in synchronous or asynchronous mode. The transmitted signals are transformed into element space by the time-varied matrixes which be used to project the highlights on the circular arc array. These methods are applied in the homing system simulation. The simulation results show that the methods can get better simulation effect of an underwater target dimension. The methods not only can simulate the working mode of conventional acoustic simulator, but also can simulate more complex target bearing changing, and can be applied to underwater vehicle homing hardware in the loop simulation.