Gas-phase OCM was investigated with various empty tubular reac-tors(quartz,ceranic and stainless steel tubes).When temperature is higherthan 680℃,the CH_4 conversions in three kinds of empty reactors are measur-able,and the gas-phase OCM becomes noticeable at 750℃ or higher tempera-ture.High temperature is beneficial to the activation of CH_4 and the dehydro-genation of C_2N_6 to C_2H_4.Residence time of reactants in the heated volumeplays an important role in the ags-phase OCM.Experiments indicated that thegas-phase OCM can be minimized by increasing reactant gas velocity or fillingthe free volume of the reactor with inert materials.Reactor surface has effecton the reaction.It may participate in some surface reactions.Based on the ki-netic results and the SEM investigation on the surfaces of reactors,a gas-phasereaction scheme of OCM is assumed. Gas-phase OCM was investigated with various empty tubular reac-tors (quartz, ceranic and stainless steel tubes) .When temperature is higherthan 680 ° C, the CH_4 conversions in three kinds of empty reactors are measur-able, and the gas-phase OCM becomes noticeable at 750 ° C or higher tempera-ture. High temperature is beneficial to the activation of CH_4 and the dehydro-genation of C_2N_6 to C_2H_4.Residence time of reactants in the heated volumeplays an important role in the ags-phase OCM. Experiments that thegas-phase OCM can be minimized by increasing reactant gas velocity or fillingthe free volume of the reactor with inert materials. Reactor surface has effecton the reaction. At may participate in some surface reactions.Based on the ki-netic results and the SEM investigation on the surfaces of reactors, a gas-phase reaction scheme of OCM is assumed.