A new type of power supply which was called oxy-fuel combustion power plant was introduced to reduce greenhouse gasses emission. In this paper the volatile emission characteristic of pulverized coal is studied under air atmosphere and oxy-fuel atmosphere. Combustion experiments of Datong bituminous coal were carried out in a wire mesh reactor at heating rates of 1 K/s, 10 K/s and 1000 K/s respectively under air and O₂/CO₂ atmosphere conditions in order to investigate the volatile emission characteristic. The concentrations of volatile (mainly CO and CH₄) emission were on-line measured by infrared gas analyzer. It was indicated that the concentrations of CO and CH₄ in O₂/CO₂ atmosphere were higher than those in air. The direct oxidation of carbon and gasification reaction between carbon and CO₂ are the main causes of the increased amount of CO. The higher concentration of CO₂ also results in the increased amount of CH₄ in O₂/CO₂ conditions.