The　reuse　of　recycled　aggregate　concrete　(RAC)　is　being　researched　all　over　the　world　and　lots　of　works　are　focused　on　the　notched　specimen　to　study　the　crack　path　of　RAC.　A　mathematical　algorithm　of　RAC　meshing　was　presented　to　explore　the　failure　pattern　in　RAC.　According　to　this　algorithm,　the　interfacial　transition　zone　can　be　defined　to　be　an　actual　thickness　at　the　micron　level.　Further,　a　new　finite　element　method　(FEM)　on　the　complementary　energy　principle　was　introduced　to　simulate　the　mechanical　behavior　of　RAC＇s　mesostructure.　The　compliance　matrix　of　the　element　with　any　shape　can　be　calculated　and　expressed　to　be　a　uniform　and　explicit　expression.　Several　numerical　models　of　RAC　were　established,　in　which　the　effecting　factors　of　the　prenotch　size,　thickness　of　ITZ,　and　the　distance　from　the　prenotch　to　the　aggregate　were　taken　into　account.　Hereafter,　these　RAC　models　were　subjected　to　uniaxial　tension.　The　effect　of　the　aforementioned　factors　on　the　crack　path　was　simulated.　The　simulated　data　manifest　that　both　the　mesh　mode　of　RAC　and　the　FEM　on　complementary　energy　principle　are　effective　approaches　to　explore　the　failure　pattern　of　RAC.　The　size　of　the　prenotch,　thickness　of　ITZ,　and　distance　from　the　prenotch　to　the　recycled　aggregate　have　a　powerful　influence　on　the　path　and　distribution　of　the　isolated　crack,　width　and　length　of　the　crack　path,　and　the　shape　and　path　of　continuous　cracks,　respectively.　Copyright　©　2021　Yao　Wang　et　al.