Abstract: The combustion systems of 5 heaters were technically reformed by PetroChina Pipeline Company in 2009.The initial atomiza-tion burners were replaced by oil gas dual-purpose burners, which favored the conversion and combustion of fuel oil/gas.Oil/gas operating parameters of the dual-purpose burners with different types were measured on different type heaters.The calculation formulae of heat load and heating efficiency in the course of testing were demonstrated, testing apparatus were introduced and the chemical compositions and heat values of fuel oil/natural gas were analyzed.Fuel oil/gas can be conveniently chosen by crude oil heater after the combustion systems were replaced by oil.gas dual-purpose burners, and that the fuel can be completely burnt in the case of low air coefficient when oil or natural gas were combusted whatever large, middle or small thermal loads were, which met the operation demands and improved the heating efficiency of heater system.Yet.lack of devices to control and monitor the combustibles during natural gas burning needed to be considered.