Passive　matrix　GaN-based　micro　light-emitting　diode　(LED)　arrays　with　two　resolutions　of　32x32　and　128x64　are　designed　and　fabricated,　and　a　micro　control　unit　is　used　to　drive　the　devices　and　display　Chinese　characters.　The　process　of　the　micro-LED　display　arrays　is　systematically　optimized,　where　emphasis　has　been　put　on　solving　two　specific　technical　problems.　First,　the　deep　isolation　trench　is　etched　in　two　steps　in　order　to　decrease　the　slope　of　the　isolation　trench　so　as　to　ease　the　p　electrode　to　climb.　In　this　way,　the　otherwise　easily　broken　p　metal　line　is　now　very　reliable.　Second,　a　secondary　growth　method　is　employed　to　deposit　SiO2　onto　the　n　metal　line　as　an　insulation　layer　between　the　p　and　n　electrode　layers.　Between　the　two　deposition　steps,　the　chips　are　rotated　with　a　certain　angle.　Therefore,　the　probability　of　pinhole　overlap　is　significantly　reduced,　and　the　insulation　between　the　p　and　n　electrode　layers　is　guaranteed.　Using　the　optimized　micro-LED　process,　micro　displays　are　fabricated　and　their　electrical,　optical,　and　thermal　characteristics　for　two　different　pixel　sizes　are　analyzed.　Experiments　show　that　the　process　optimization　above　helps　realize　the　outstanding　properties　of　the　micro-LED　display　arrays,　increase　the　device　and　system　reliability.　The　work　will　contribute　to　the　implementation　of　the　GaN　based　micro-LED　technologies　in　real　life.