The　non-homogeneous　longitudinal　magnetic　filed　is　applied　to　the　process　of　spray　transfer.　With　high　speed　camera,　the　mechanics　of　drop　transfer　is　studied.　Also　the　reason　of　spatter　formation　is　analyzed.　The　experimental　results　show　that　arc　and　liquid　metal　jet　are　both　deviating　from　the　axis　of　wire　in　a　certain　angle　and　rotating　in　high　speed.　Meanwhile,　the　frequency　of　drop　transfer　increased.　When　the　liquid　metal　jet　is　shorting　out　the　welding　pool,　the　spatter　is　formed.