Abstract: High pressure sales gas may appear to have retrograde phenomenon because of pressure reduce and condense liquid drops of heavy hydrocarbon in gas phase at the special operating conditions of gas transportation and distribution system. Therefore the dew point index should be stipulated to guarantee safe and smooth operation of the system. Because composition of natural gas is very complicated and its phase behavior is absolutely different from other gas mixtures of single or multiple components, measurement of hydrocarbon dew point for sales gas is extremely difficult. Three methods of hydrocarbon dew point measurement and relative traceable way are briefly introduced in this article. Methods using manual or automatic hydrocarbon dew point chilled mirror instrument are that of physical property determination. These methods are not provided with traceability and the uncertainty of results of determination can not be assessed. The technical characteristic of PHLC method is that of establishment traceable procedure for chilled mirror instrument based on substantial relationship between hydrocarbon dew point value and PHLC at same pressure. Presently the accuracy of an advanced chilled mirror instrument has already reached ±0.5 ℃. The method for calculation of hydrocarbon dew point by state equation is based on strict chemical thermodynamics and its application is not very popular because of influences of sampling representativeness, analytical accuracy and data processing.