A　handwriting　detecting　system　based　on　micro-accelerometers　and　micro-gyros　is　proposed,　and　the　algorithm　of　the　detecting　system　is　also　described　in　detail.　The　micro-accelerometers　and　micro-gyros　mounted　on　the　pen　are　used　in　this　dynamic　handwriting　acquisition　system　to　acquire　the　dynamic　information,　and　obtained　data　are　transmitted　to　computer　for　data　processing　and　feature　analysis　through　a　serial　port　after　A/D　conversion.　The　motion　track　of　the　pen　in　the　3-D　space　can　be　recognized　through　computing　the　matrix　of　attitude　angles　and　the　dynamic　information　of　the　pen　is　mapped　on　the　2-D　plane.　Then,　the　information　of　handwriting　can　be　recurred　on　the　writing　plane　by　an　integral.　Finally,　this　paper　introduces　the　influence　of　gravity　acceleration　on　the　handwriting　recurrence　in　the　movement　of　the　pen,　gives　a　solution　to　get　pure　movement　acceleration　from　the　gravity　acceleration　detected　by　the　micro-accelerometer,　and　describes　the　sensor　calibration　method.　Experimental　results　prove　the　designed　system　to　be　feasible.