Abstract: In order to understand the laws of generation and variability of CO in the process of oxygen-free pro-grammed temperature of coal,the programmed temperature technology and time resolved spectroscopy were used to accomplish this experiment. The time resolved spectroscopy spectrograms were gathered during program control heat-ing in oxygen-free conditions. The laws of generation and variability of CO were revealed. The equation was estab-lished to explain the functional relationship between the amount of CO generated and the mass fraction of coal. The study shows there are no CO generated within the scope of 30 - 370 ℃ due to low pyrolysis temperature. Within 370-650 ℃ in which the coal weight loss is fastest,the CO concentration increases gradually with increasing tem-perature,which reaches peak at 641． 5 ℃ . Within 650-800 ℃ ,the CO concentration decreases gradually and ulti-mately disappears with increasing temperature, because the oxygen-containing functional groups related to the CO generated are gradually depleted.