Abstract: This study is carried on to explore a feasible approach to transfer the irregular powder,such as Ti powder and bronze powder,into spherical powder by "balling effect".The results indicate that:(1)the balling ability of mental powder can be ranked by a balling factor K which accounts for the influence of particle size,density,special thermal property,boiling point as well as laser absorbing rate;(2)when the scanning speed vequals laser power P multiplying K,the irregular particle will be transformed into spherical powder.