A　quantum　secure　direct　communication　(QSDC)　protocol　is　presented.　In　the　proposed　protocol,　the　omega　state　is　introduced　to　detect　the　eavesdropping　during　the　quantum　communication,　eavesdropping　behaviors　will　change　the　state　of　the　omega　state,　and　the　sender　Alice　and　the　receiver　Bob　detect　eavesdropping　through　the　state　measurement　results.　The　relationship　between　the　amount　of　information　that　the　eavesdropper　gets　and　the　probability　of　being　detected　is　also　given.　Compared　with　the　original　QSDC　protocol　based　on　the　Bell　state,　when　the　same　amount　of　information　is　obtained,　the　eavesdropper　must　face　a　higher　detection　probability　in　the　proposed　protocol,　and　the　eavesdropper　mostly　can　obtain　0.676　(bit)　of　information.　The　security　analysis　is　also　given,　and　the　result　indicates　that　the　proposed　protocol　is　more　secure.　A　simulation　based　on　the　law　of　large　number　and　the　Monte　Carlo　method　is　also　given,　and　the　mean　square　error　is　introduced　to　describe　the　similarity　between　the　simulation　data　and　the　theoretical　value.　The　simulation　result　indicates　that　the　proposed　security　in　an　ideal　environment　and　the　security　analysis　are　correct,　and　the　proposed　protocol　is　more　secure　by　sending　more　quantum　particles　in　detecting　eavesdropping.