In　order　to　manufacture　deep　microslit,　a　new　micro　EDM　process　was　developed.　With　this　method　a　raw　rod　electrode　with　negative　polarity　is　used　to　scan　a　metal　plate　to　form　a　through　slit.　Then　the　rod　electrode　is　moved　perpendicularly　to　the　slit,　with　certain　distance　from　the　center　of　the　slit.　Micro　flat　electrode　is　obtained　after　the　raw　rod　electrode　is　fed　into　the　plate　in　the　axial　direction　of　the　rod.　Micro　slips　are　achieved　by　scan　machining　with　the　micro　flat　electrode　finally.　At　last　deep　micro-slits　with　aspect　ratio　of　18:1　and　of　parallel　and　equal　width　have　been　successfully　achieved.　Compared　to　the　methods　of　reverse-EDM　with　block　electrode　and　WEDG,　the　self-manufacturing　method　of　flat　electrode　is　adopted　to　avoid　the　requirement　for　precision　positioning　between　the　electrodes.　To　manufacture　micro　slit　on　metal　part,　micro-EDM　using　flat　electrode　is　suggested,　which　may　have　less　electrode　wear　and　higher　efficiency　than　that　of　using　rod　electrode.