The study was carried out on the burning test-bed which was controlled by Programmable Logic Controller (PLC) model and diesel was used as the fuel. The thermodynamic characteristic of oxygen-enhanced combustion, including fuel consumption, flue gas volume, flue gas components’ volume concentration, theoretical flame temperature, flame emissivity, energy efficiency and thermal efficiency, etc, were analyzed. The results showed that: with oxygen concentration was increased from 21% to 30%, fuel consumption was decreased by 40.6% and flue gas volume was decreased by 57.5%. Additionally, higher oxygen concentration leaded to higher theoretical temperature and stronger flame blackness because of the decreasing of N2 volume in supporting air. What’s more, the decreasing of energy brought away by flue gas and the thermal efficiency were both increased with the increasing of oxygen concentration.