In order to measure the mean height of long distance burst, a double line scanning CCD measurement system is established and its theoretical model is built.First, telescopic optical system is used to image the burst, and the image is transformed by a cylindrical lens.Then, Zemax software is used to simulate the optical system, whose spot diagram show that the system can effectively measure the mean height of burst within 5 meters at a long distance of 20m.Finally, the spot center is acquired by means of the curve fitting and linear calibration is carried out for uncertain parameters of the system.Experimental results indicate that the maximal height is 3 m approximately at a long distance of 20 m.The mean error is 1.95%.The presented system can reach the acquirement of long distance and wide range.Furthermore, the uncertainty of distance can be eliminated naturally by using the double line scanning CCD system.