The use of radar to detect micro-Doppler frequency peculiar to the ballistic missile is a new method for target detection,and the selection of the scattering points on the target body is one of the key factors in the extraction of micro-Doppler characteristic parameters.Firstly,the motion model of the warhead of the ballistic missile is established and the extraction method for the micro-Doppler characteristic parameter of the warhead target based on the time-frequency analytical method is given.Then,the scattering points on the target body are classified into four types according to the different positions of them.By simulating the extraction of micro-Doppler characteristic parameters,the properties of the characteristic parameters changing with the scattering point are analyzed.The simulation results show that:1) The fretting characteristic parameters of the missile can be effectively extracted by selecting the scattering points from the top,the edge of the bottom and the conical surfaces of the missile cone,with the total number less than 9;and 2) With the increase of the number of the scattering points,the difficulty for extracting the fretting characteristic parameters is correspondingly increased,to the extent that it is impossible to extract the fretting characteristic parameters.