With the demand analysis of automobile covering part molds, build-up welding was stated to be used in the designing and manufacturing of stamping mold and the advantage was pointed out. The processes of build-up welding for cast iron were illustrated, including the structure of build-up welding in the cutting edge of stamping mold, welding rod selection, the procedures of build-up welding, grooves, welding equipments, welding processing, operation attentions, heat treatment after welding, manufacturing way of cutting edges, etc.. The quality checking ways of build-up welding in blades were introduced. Build-up welding can shorten the period of mold manufacturing, reduce costs and increase productivity.The economic benefit is very significant.