The characteristics of the flame behavior of a non-premixed oxy-methane jet were investigated by increasing the carbon oxide (CO) mole fraction in a fuel jet. In the current study, a lab-scale furnace was used with a slot-type burner to modify industrial furnaces. The flow velocity was fixed at u(F) = 25 m/s for methane and u(OX) = 25 m/s for oxygen. The mole fraction of CO gas in a fuel jet (X-CO) was varied from X-CO = 0% to 30% over 10 steps. To observe the flame behavior of a non-premixed oxy-methane jet, flame stabilization and flame luminescence were experimentally measured. The objective of the current study is to investigate the effect of CO addition in a fuel jet on the flame stabilization, flame spectra, and flame behavior of a non-premixed oxy-methane flame. From the experimental results, the flame stabilization area expanded as the CO mole fraction in the fuel jet decreased. The intensity of light emission in the rage of Delta lambda = 303-313 nm increased as the CO mole fraction decreased. In addition, the flame length became longer and the flame slope was more declined as lee CO was added. (C) 2013 Elsevier Ltd. All rights reserved.