The flame propagation law of H-2 and O-2 premixed gas explosion was studied in a small-scale pipeline experiment with a full size transparent window set up. The experiment consists of a small-scale blast pipe, gas distribution system, ignition system, pressure data acquisition system, high-speed photography system and so on. By setting different conditions of initial concentration and initial pressure, the flame propagation law was studied. Flame propagation images were obtained through a high-speed photography collection system and analyzed for its propagation law. The explosion flame propagation speed was calculated through image processing by MATLAB. The results show that under the condition of the same initial concentration, the higher the initial pressure, the larger the explosion flame acceleration. The maximum explosion pressure has approximate linear relationship to the initial pressure. Under the same initial pressure; when the equivalent ratio is closer to 1, the flame acceleration rate becomes larger, and the explosion pressure reaches the maximum value. (C) 2017 Elsevier Ltd. All rights reserved.