A　topology　optimization　design　method　for　the　prestressed　plane　entity　steel　structures　is　proposed.　The　optimization　mathematical　model　is　established　in　such　form　that　the　cables＇　pretension　force,　unit　size　and　the　structural　topology　are　referred　as　the　design　variables,　the　element　stress　as　constrain　condition,　the　minimum　of　structural　weight　as　the　objective　function.　In　order　to　solve　the　problem,　firstly,　an　optimization　model　between　calculate　cables＇　pretension　force　and　the　structural　weight　is　established　by　fully　stress　design,　and　cables＇　pretension　force　is　calculated　by　solving　the　model　and　the　unit　size　is　selected　by　fully　stress　design.　and　then　topology　optimization　design　is　completed　through　deleting　lower　thickness　plane　entity　elements　which　classified　according　to　threshold　value.　The　result　of　the　examples　in　this　paper　coincides　with　conclusion　of　corresponding　structural　performance,　and　this　indicates　the　optimization　design　method　in　this　paper　is　practicable　and　can　provide　theoretical　method　for　prestressed　steel　structures＇　system　innovation.