Abstract: To solve pressure instability of the commercially available gas-liquid mixture adding device,the floating head type is designed.The device uses the floating head to dose,which could make the liquid added stably and automatically without external force and the pressure adjusted according to the actual situation.It consists of storage tank with lightweight telescopic pipe and floating head,dosing tank and mixing tank.Under the condition of a certain pressure,it can make use of fine atomization nozzle to atomize liquid additives so that they can mix with natural gas better and be added stably.The device can be used for welding and cutting operations,which is beneficial to improving the work quality and reducing the cost of operation and safety.