This work aimed to evaluate the effects of C2H6, C2H4, CO, H-2, and their mixture on the explosion characteristics of CH4. The flammable limits tests were performed in an upward propagation cylindrical vessel with a volume of 3.4 L The explosion properties of the mixtures were tested in a standard 20 L spherical chamber. All experiments were conducted at room temperature and at ambient pressure, with a relative humidity range from 52 to 73%. The parameters of flammable limits (upper flammable limit (UFL) and lower flammable limit (LFL)), explosion risk value (F), peak explosion pressure (P-max), maximum pressure rise rate ((d(p)/d(t))(max)), and the gas deflagration index (K-G) were observed and analyzed. The laminar burning velocity (S-L) of the mixtures was determined by an outwardly propagating spherical flame method. The results indicated that the existence of C2H6, C2H4, CO, H-2, and their mixture lowered the flammable limits of CH4-air, enlarged its flammable range, and increased its explosion risk value. Furthermore, with regard to the fuel-lean CH4-air mixture, the addition of the mixed gas with volume fraction of 2% would enhanced its P-max, (d(p)/d(t))(max))KG, and SL by 393%, 253%, 253%, and 13.6% respectively. However, the mixed gas negatively affected those of the fuel-rich mixture, reduced those parameters by 21.9%, 73%, 73%, and 29% respectively. With regard to the stoichiometric condition (9.5% CH4-air mixture), the mixed gas slightly lowered P-max, (d(p)/d(t))(max), and KG; however, it reduced SL more abruptly with a reduction of 29.6%. (C) 2017 Elsevier Ltd. All rights reserved.