Abstract: In this paper,based on the electronic mobility detecting technique,the particulate size distributions of welding aerosol of selling common electrodes during welding is measured on real time by means of DMPS method under the control of a microcomputer.At the same time,the shapes of welding aerosol particles(WAP) are analyzed by TEM method of direct sample preparation.The feature of the complex distribution with multi-peaks of WAP during welding is found for the first time.Using the zoning analysis method,the distribution function describing distribution feature of WAP can be given.The particulate groups of each peaks for E4303 electrode generally follow logarithmic-normal distribution.It is of great importance to explain generation mechanisms of WAP and its cha-racter,to control effectively welding fume.