Abstract: In order to correct the systematic differences of analysis results between high altitude areas in Guizhou Province and low altitude areas,seven cigarette samples of different tar,nicotine and CO contents were determined under ISO smoking regime in six laboratories at different altitudes.The results indicated that:1) With the rise of altitude,the measurements of tar and CO reduced to different extents.2) The reduction of measurements was more obvious for the samples of tar delivery less than 8 mg/cig and CO delivery less than 11 mg/cig.3) Taking tar delivery of 8 mg/cig and CO delivery of 11 mg/cig as boundaries,the correction equations of tar and CO measurements at the atmospheric pressure of about 90 kPa against their counterparts at 100 kPa were established separately and verified,and the correction results were satisfactory.