Abstract: Based on the highlight method, this paper builds up the model of the radar target especially the near field. Themethod of computing the target echo signal amplitude，time delay and Doppler shift is discussed. The database of the propertiesof near field, which is generated by the fuse antenna, is made using FDTD method.．Combining simulation of board-lever circuitwith computing of near field，the simulator was made for fuse system. And by means of this simulator the imitative analysis andcalculation on fuse system can be more reliable and accurate. In the end the result of time-domain simulation demonstrate thatthe simulator can be effectively applied in the synthetic test system to the fuse of the weapon system.