The brief procedure of how to get a gas mixture of low concentration and high accuracy with the double balance weighing method was described. This method requires two balances of both different ranges and high resolutions, also tow sets of equipment for introducing Ar, Ne, Kr, Xe, and the Nitrogen for balance gas. Two sets of equipment were fulfilled according to the described procedure without any backflow of the component gases. The residual gas in the filling equipment was analyzed to correct the mass of the component gases filled into the mixture gas. By this way, the concentration of Kr and Xe in the preparing mixture gas, is about 0.1%, with the maximum uncertainty of about 0.1%.
