A　new　way　of　precision　machining　was　studied　through　the　experiments　of　Electrolytic　In-Process　Dressing　(ELID)　precision　grinding　and　ultra　precision　lapping　and　polishing　for　W-Mo　metal　alloy.　First　a　22nm(Ra)　surface　was　obtained　through　the　ELID　grinding,　last　a　1　1　nm(Ra)　surface　was　obtained　after　the　process　of　lapping　and　polishing　with　0.1　similar　to　0.3　N/cm(2)　pressure,　60　similar　to　100　r/min　rotational　speed　and　other　optimized　parameters.　Meanwhile,　the　formation　mechanism　of　ultra　precision　mirror　surface　of　the　alloy　was　also　analyzed.　The　experiments　prove　surface　quality　of　the　work　piece　was　guaranteed　by　ELID　grinding,　and　which　was　also　greatly　affected　by　some　parameters　in　lapping　and　polishing　such　as　pressure,　rotational　speed.