In high-pressure environment, the high density of the droplets leads to attenuate both the incident laser beam and the emitted signals. For the quantitative measurement, the intensity of the attenuated signal should be corrected. Therefore, Optical Line Patternator (OLP) was applied to get the original distribution of the spray at high ambient pressure. Because OLP uses laser beam instead of laser sheet to scan the spray, the noise effect of multiple scattering, caused by increasing number density of droplet in high-pressure environment, is also reduced significantly. The line image of Mie-scattering was captured simultaneously in the path of each laser beam by using CCD camera. The transmission that was calculated the fraction of the intensity of incident laser beam and the attenuated intensity after traversing spray region, was measured by using a photo-diode. The distribution of attenuation coefficient in the spray was obtained by processing the transmission and Mie-scattering distribution with the algebraic reconstruction technique. From the distribution of extinction coefficient, we can obtain the accurate surface distribution from Mie-scattering from laser-induced fluorescence signal. OLP is expected as a suitable method that can investigate the characteristics of relatively large spray under the high-pressure environment such as liquid rocket engine.