As the necessity of forest conservation and management has been increased, various studies on measuring forest biomass have been actively performed. In this study, for forest biomass measurement, we estimated mean tree heights from airborne LIDAR data. We grouped the LIDAR data into a grid, and generated a histogram of point heights for each cell. By analyzing the histogram, we estimated the maximum and mean tree heights, and the mean crown height. We applied this method to the LIDAR data acquired from a mixed forest area and compared the results with field measurements. The estimated mean tree heights were underestimated by about 0.6 m and the mean crown height showed the RMSE of 2m. The proposed method will be effectively utilized for the accurate determination of forest biomass.