The invention discloses a C2 post-hydrogenation acetylene removing method. A column top effluent from a deethanizer in a C2 post-hydrotreatment device is fed into a thermal insulation reactor for selective hydrogenation, and thus acetylene in the effluent can be removed. A Fe family selective hydrogenation catalyst is adopted as a hydrogenation catalyst, a high temperature resistant inorganic oxide is adopted as a carrier, and hydrogenation raw materials mainly consist of 0.98-2.2% of acetylene, 11.2-30.3% of ethane and 65.0-85.0% of ethylene. The reaction conditions are that the inlet temperature of a thermal insulating bed reactor is 40-100 DEG C, the reaction pressure is 1.5-2.5MPa, and the gas volume airspeed is 2000-10000 h<-1>. The C2 post-hydrogenation acetylene removing method disclosed by the invention is moderate in catalyst reaction activity, good in operation elasticity and good in ethylene selectivity, and the 'green oil' generation amount is far less than that of an acetylene removing method using a noble metal catalyst.