The utility model relates to a multifunctional gas iron without an iron head, which uses liquefied gas as a heat source. The iron comprises a gas inlet valve, a gas tank, a gas inlet pipe, a gas delivery pipe, a regulating switch for the liquefied gas, a regulating switch for air, a changeable welded joint, a gas reflecting flaming net, etc. The changeable welded joint is provided with an igniting hole, and the weld can be carried out without an iron head; the iron head can be also sheathed on the changeable welded joint and an igniting hole on a closing joint. The iron head comprises an ignition hole, a temperature-rising cavity, a regulating hole for air and a heat-transferring hole. The utility model, which is preheated for only 28 seconds-40 seconds, has the advantages of long service life, convenient use and portability. The power can be arbitrarily regulated between 15W and 1500W, and the utility model has a plurality of functions of welding tin, copper, lead, silver, plastics, etc.