Objective To monitor the long - term trend of the concentration of radon in the air of the national radiation envi- ronment quality control point. Methods Solid state nuclear track method was used in measurement, Radon concentration measurement data on different point position measurement are normalized. The influence of humidity, air pressure, high of 220 Rn measurement results were analyzed. Results The measurement method was tested in standard radon laboratory, and the error of measurement results was 7.1%. Conclusion Solid state nuclear track method in the standard radon laboratory scale c...