The aim of this research is to investigate the combustion of used engine oil in a vertical circular burner. The burner was equipped with 5 air suppliers in different levels and air flow rate from each supplier can be adjusted. In the experiment, the air was supplied to the burner twice, in the first and the second levels, to burn the fuel 2 times. The air was supplied to the first level and the incompletes combustion was occurred. Also, the heat from the combustion in this level would help to vaporize the residual fuel. The exhaust gases and residual fuel vapor from the first level were then flow to the second combustion zone and mixed with the air supplied in this level and the complete combustion was accomplished. The tests to study the impact of the air supply position and the flow rate of air supply on the temperature profile and the emission were carried out. The thermocouples were installed along the length of the burner to measure the temperature in the burner and emission of the combustion was also measured. The results from the tests of the combustion with single-air supply system and those of with double air supply system were compared. The preliminary experimental results indicated that the single-air supply system has the higher temperature profile and higher emission than those of double air supply system. Based on preliminary experimental results, the double air supply system is chosen for additional experimental studies. The results revealed that the lower temperature profile and higher emission were found in the double air supply burner when increased the distance between the air suppliers. In addition, increased in air flow rate of the air supplying in the first level resulted in an increase in temperature profile and emission. It can be concluded that the used engine oil which is the waste that increase with the number of the car, are able to use as the alternative fuel in the vertical circular burner.