Weld bead surface quality has an important effect on the quality of prototyped products .In the paper, hierarchy analytical theory, combined with the experiment, is employed to determine the weld bead surface quality synthesis evaluation weight coefficient of bead uniformity, bead continuity and spatter. The membership degree tables of bead uniformity, bead continuity and spatter are created by using fuzzy theory. Thus a evaluation method of bead surface quality is established and applied to evaluate practical bead surface quality. It is approved that the calculation value accords with the actual result, which proves the evaluation method of bead surface quality is effective.