The effects of obstacles on methane explosion inside a narrow space and its suppression by ultra-fine water mist are investigated experimentally. Two PCB pressure transducers and two E12-1-C-U fast response thermocouples are used to obtain the explosion pressure and temperature, respectively. A Fastcam Ultima APX high speed video camera is used to visualize the process of methane explosion with the influence of obstacles and ultra-fine water mist. The results show that the explosion would be strengthened by the obstacles, while the further strengthening occurs to the cases where the obstacles are farther from the ignition electrode. In addition, the more the obstacles are, the stronger the explosion strengthening will be. The reinforcement effect on gas explosion of the square ring is a little stronger than the column one. The suppression of methane gas explosion containing obstacles with ultra-fine water mist is very effective. KEYWORDS: gas explosion, explosion overpressure, explosion suppression, water mist