Abstract: The laminar flame speeds of CH₄/H₂/air mixtures were experimentally studied at elevated initial temperatures using the Bunsen burner method combined with the Schlieren technique， and the corresponding cases were computed using CHEMKIN-PRO. The effect of initial temperatures on the propagation characteristics of laminar premixed flames was discussed from the perspectives of thermodynamics and chemical kinetics. The results show that the laminar flame speeds of the mixtures at 293-500K can be predicted well by GRI-3.0 mechanism. The greater increments of laminar flame speeds of mixtures are presented at higher H₂ fractions under all tested initial temperatures. The laminar flame speeds and adiabatic flame temperatures of mixtures almost linearly increase with a growth of initial temperatures with the same equivalence ratios. With the rise of initial temperatures， the dominant promotion of H+O₂=O+OH on the mass burning rates of mixtures can be enhanced by the great growth of the mole fractions of H radicals. Therefore， the laminar flame speed of CH₄/H₂/air mixtures significantly increases at elevated temperatures.

Key words: Bunsen burner; laminar flame; flame propagation; H₂ fraction; GRI-3.0 mechanism