Aerosol scale height is one of the important quantities, and it indicates the aerosol concentration and the vertical distribution characteristics of extinction coefficient profile. The aerosol extinction coefficient profile is obtained with micro pulse lidar in northwest China, and the atmosphere vertical optical thickness is measured by sun-photometer. We can obtain aerosol scale height by fitting the measured data. Results show that the aerosol scale heights obtained by the two different methods have a good linear correlation, and the correlation coefficient is larger than 0.87. A statistical analysis for aerosol scale height in northwest China is carried out. The variation in aerosol scale height with time, region and climate condition is presented. The research has significance in studying the characteristics of aerosol variation in northwest China and establishing aerosol patterns.