A new type of ultraviolet imaging method is introduced, it is useful to specific pollution gas in the pollution sources. The method is based on Lambert-Bill absorption law and reproduces the two-dimensional distribution of pollutant concentration in space with high temporal and spatial resolution by using an ultraviolet band pass filter. The measurement system is built in the laboratory to detect SO2, the measuring method about imaging technology is set forth, and the linear response and sensitivity in regard to that is analyzed. The results show that the linear response is positive and the response coefficient is as high as 0985. The sensitivity of different imaging area changes, the difference is between 1%～3%. At the same time, the accuracy of this method is discussed to get accurate SO2 column density, the result in the laboratory shows that the error about the method is around 1% and the accuracy is higher. At last, the detection limit of the method is analyzed and the space distribution of the target gas SO2 on cross section in the sample pool is parsed according to the linear least squares fitting method.