Unmanned　aerial　vehicles　(UAVs)　are　already　widely　used　to　provide　both　relay　services　and　enhanced　information　coverage　to　the　terrestrial　Internet　of　Things　(IoT)　networks.　IoT　devices　may　not　be　able　to　handle　heavy　computing　tasks　due　to　their　severely　limited　processing　capability.　In　this　paper,　a　multi-UAV　deployment　for　mobile　edge　computing　(MEC)　enhanced　IoT　architecture　is　designed,　where　multiple　UAVs　are　endowed　with　computing　offloading　services　for　ground　IoT　devices　with　limited　local　processing　capabilities.　In　order　to　balance　the　load　of　UAVs,　this　paper　proposes　a　multi-UAV　deployment　mechanism　which　is　based　on　the　difference　evolution　(DE)　algorithm.　Meanwhile,　the　access　problem　for　IoT　nodes　is　formulated　as　a　generalized　assignment　problem　(GAP),　and　then　an　approximate　optimal　solution　scheme　is　used　to　solve　the　problem.　Based　on　this,　we　realize　the　load　balancing　of　multiple　UAVs,　guarantee　the　constraint　of　coverage　range　and　meet　the　quality　of　service　(QoS)　of　MEC　networks.　Finally,　sufficient　simulations　prove　the　effectiveness　of　our　proposed　multi-UAV　deployment　algorithm.