Abstract: Based on square transparent experimental tube with 1.5m long, photoelectrical transducer, pressure transducer and high-speed video camera was used to set up optical and pressure signal testing system. The obstacles are of 4 types (i.e. plates, triple prisms, cuboids and cylinders) and three kinds of blockage ratios (i.e. 20%, 40% and 60%). The results in the experiment show that: (1) plates and triple prisms increase flame speed and overpressure much larger, and cuboids are intermediate, while effects of cylinders are comparatively limited. (2) The obstacles can remarkably accelerate the flame velocity and pressure, and the irregularities of their surface are the main factor contributing to the flame turbulence. (3) There is a small difference in the initial stage of flame acceleration, and the flame speed and overpressure are increased obviously when the flame comes across the obstacles. The research has some effect on preventing and controlling explosion disaster of methane in mine and other combustible gases in pipelines.