Abstract: The conception and modeling of droplet forming in gas metal arc welding short circuiting transfer was proposed.By virtue of Micro Focus High Speed Photography technique and digital image processing technique, the gravitation, electromagnetic force and the maintaining force rooted in the surface tension of the little guttate metal in droplet forming process were analyzed and calculated quantificationally.The results showed that the maintaining force rooted in the surface tension was much greater than the detached force composed of the gravitation and the electromagnetic force.furthormore, the fusion of the wire is considered here.All the factors above resulted in the fact that the little guttate metal can keep its shape while spreading on the tip of the wire.The validity of this model has been proved by experiment.