Micro-　and　nano-particles　can　be　trapped　in　locally　strong　or　weak　regions　of　a　non-uniform　electric　field　through　the　effect　of　dielectrophoretic　principle.　Recently,　a　novel　optoelectronic　tweezers　(OET)　based　on　optically　induced　dielectrophoresis　(DEP)　was　demonstrated　by　Chiou　et　al.　[1]　for　effectively　trapping　and　manipulation　of　cells　and　latex　particles.　The　OET　allows　an　optical　beam　to　create　a　virtual　electrode　on　a　photoconductive　surface,　which　produces　a　highly　non-uniform　electric　field.　Here　we　simulated　the　electric　field　distribution　produced　by　a　light-induced　ring-shaped　electrode　for　particles　trapping.　Then,　we　simulated　the　DEP　trapping　effects　from　a　real　microelectrode　that　could　be　fabricated　on　a　glass　substrate　to　replace　the　virtual　light-induced　electrode.　This　is　to　compare　the　efficiencies　of　OET　and　microelectrode　induced　DEP　effects.　We　also　derived　the　smallest　radiuses　of　the　polystyrene　bead　which　could　be　potentially　trapped　in　the　OET　device　and　the　real　electrode　structure.　Finally,　we　designed　and　analyzed　a　33　electrode　array　to　explore　the　possibility　of　arbitrarily　trapping　and　manipulating　single　particles　using　the　real　microelectrodes.　©　2008　IEEE.