Experimental and numerical studies on the laminar burning velocity of hydrogen-air mixtures were performed. Measurements of laminar burning velocities were conducted using a new technique based on particle tracking velocimetry (PTV) and image processing for burner-stabilized flames in a high-pressure chamber. Equivalence ratios of the mixtures were varied from 0.6 to 3.0 for the pressure range from 0.1 to 0.5 MPa. A numerical simulation was conducted considering detailed reaction mechanisms and transport properties At high pressures, the experimental and numerical results agreed reasonably well with each other for mixtures of equivalence ratios of 1,0 and 2.0, while discrepancies were seen for the equivalence ratio 3.0. These discrepancies can be diminished effectively by modifying the rate-coefficient expressions of recombination reactions. (C) 2000 Elsevier Science Inc. All rights reserved.