With　the　development　of　smart　power　grid,　the　operation　mode　of　power　grid　is　time-varying,　which　leads　to　the　complex　security　problems　of　power　grid.　Buffer　overflow　has　become　the　most　serious　security　threat　of　smart　grid.　The　embedded　network　security　equipment　needs　more　ability　to　resist　buffer　overflow　attack.　Based　on　the　basic　principle　of　buffer　overflow,　a　multi-level　anti-buffer　mechanism　is　put　forward　and　applied　to　embedded　security　devices　in　this　paper,　which　can　fundamentally　curb　the　occurrence　of　buffer　overflow　and　maintain　a　good　network　transmission　environment　for　smart　grid.　©　2019　IEEE.