Abstract: Because the evaluation of wire vertical characteristic through manual welding operation methods was poor accuracy,only was qualitative,not quantitative and further limited to enhance the level of flux cored wire,Hannover Arc analyzer was used to quantitatively analyze the arc physical characteristics and the performance parameters of vertical welding with four kinds of stainless steel flux-cored wire.Through analyzing the relation of the probability density distribution of arc voltage,current,short circuit time,their standard deviation and metal transition,the experimental results showed that the standard deviation of current,voltage and short circuit time were smaller,the effective transition ratio of the larger short-circuit was bigger,the uniformity and stability of wire droplet transition became better,splash became smaller,the characteristics of vertical welding became better,so the optimizing design of all-position flux cored wire formulation had great practical significance.