Accurate online gas mixer who adjusts mixing ratio is including first admission line, second admission line, blender and the mixed pipeline of giving vent to anger, follow airflow direction on the first admission line and set gradually first manual governing valve, first manometer and first -class gauge, set gradually the manual governing valve of second, second manometer and second flowmeter along airflow direction on the second admission line, the second admission line is connected with two spinal branch admission lines through a three -way pipe. The utility model relates to a rationally, realize homogeneous mixing gaseous more than two kinds at pipeline carrier gas in -process to can adjust the air input according to mixing ratio, adjust the precision height, mix effectually. The utility model provides a manual regulation valve high -temperature and corrosion resistance performance is good, reaches good sealed effect to easily adjust the leakproofness, the maintenance is changed conveniently.