Abstract: For the gimbaled warhead, attacking the target in a choosen position is quite necessary. Based on the character that miss distance will certainly lead to an angle velocity of the seeker in the encounter segment of an air defense missile when attacking the target in reversing track, the geometry relations of the sight angle, sight angle velocity, relative velocity between missile and target, and the radial velocity are analyzed. A method of miss distance measurement using the sight angle, sight angle velocity and Doppler frequency is advanced. The problem of appreciable error arising in the measurement using distance data is solved. At the same time, the measurability of parameters is analyzed, too. At last, with the simulations in two different situations that the seeker can give and cannot give sight angle velocity, the validity and utility of the method is proved.