The　research　presented　in　this　paper　focuses　on　the　laser-powder　interaction.　Through　the　experiment　with　metal　powder　in　micrometers,　we　found　that,　in　an　invariable　laser　power　density,　the　thickness　of　the　final　fabricated　thin　wall　was　similar　to　the　geometrical　dimension　of　the　powder　line,　but　could　be　much　greater　than　the　laser　focus　spot,　even　greater　than　two　orders　of　magnitude.　Furthermore,　this　paper　showed　that,　the　unmelted　and　semi-fused　particles　were　concentrated.　Thus,in　this　paper,　combining　the　optical　scattering　theory　with　capillarity　and　infiltration　theory　pointed　out　the　inducement　effect　of　laser　and　the　self-melting　of　powder.　Based　on　the　experimental　phenomena　and　theory,　we　get　our　own　ideas　on　the　laser　micro-fabrication.