In order to develop a simple and effective method for determining the rate of the Maillard reaction in non-fat dry milk, the carbon dioxide content of the headspace as an indicator were used and the amount of correlation between CO₂ content and brown color development were determined by the gas chromatograph. There is a high correlation between brown color and CO₂ content. The use of gas chromatography to analyze the CO₂ in the headspace of samples is a quick, simple and effective method of monitoring the Maillard reaction. Volatile concentration increases with storage time and varies inversely with oxygen content. Lysine is more effective than glucose in catalyzing the Maillard reaction. Product samples can be stored at 55° and 65℃ to accelerate the rate of the Maillard reaction and shorten testing period, but product stored at 75℃ is degraded too rapidly to be of any real use.