A　copper-water　flat　plate　heat　pipe　with　intersected　micro-grooves　was　developed　for　cooling　electronic　devices　in　this　paper.　The　effects　of　heat　flux,　working　fluid　filling　ratio　and　inclination　angles　on　thermal　performance　of　the　flat　plate　heat　pipe　was　tested　and　investigated.　The　laboratory　tests　show　the　optimal　filling　ratio　of　the　heat　pipe　is　about　65%.　Excellent　thermal　performance　is　also　observed　in　unfavorable　titled　positions　including　vertical　and　anti-gravity　orientation　at　65%.　The　smallest　overall　thermal　resistance　is　obtained　in　horizontal　position　and　the　maximal　thermal　resistance　is　observed　in　vertical　position.　The　influence　of　inclination　angles　on　thermal　performance　of　the　heat　pipe　in　both　axial　direction　and　radial　direction　is　also　investigated.　As　the　heat　pipe　is　tilted,　the　ability　of　temperature　leveling　in　radial　direction　is　enhanced,　nevertheless,　the　capacity　of　heat　transfer　in　radial　direction　decreased　at　the　same　time.　©　(2013)　Trans　Tech　Publications,　Switzerland.