The characteristics of light emission of a premixed oxy-methane flame were experimentally investigated in atmospheric conditions (T-infinity, = 24 degrees C and P-infinity = 1.01325 bar). The objectives of the current study are to investigate the flame luminescence and flame spectra of a premixed oxy-methane flame in a cylindrical tube burner and to derive an empirical formula describing the relationship between chemiluminescence intensity ratio, fuel flow rate, global equivalence ratio, and diluent mole fraction. The mixture velocity at nozzle exit (u(o)) was varied in u(o) = (15-35) m/s and the global equivalence ratio (phi(G)) was changed from 0.4 to 2.0 with a cylindrical tube burner of d(o) = 2.03 mm. A spectrometer and ICCD (intensified charge-coupled device) camera were used to detect flame chemiluminescence with narrow band-pass filters and lenses. The light emission of a laminar premixed oxy-methane flame was more dominant at A = 308 nm than at other wavelengths from the measurement of spectral intensity. The intensity of OH* and CH* increased with an increase in mass flow rate of fuel (m(F)), adiabatic flame temperature (T-Ad), and equivalence ratio (phi(G)) in = 0.5-1.1. The intensity ratio of OH*/CH* was expressed as a function of the fuel flow rate, equivalence ratio, and diluent mole fraction (X-D). (C) 2016 Elsevier Ltd. All rights reserved.