Recently,　the　terahertz　(THz)　photon-assisted　tunneling　(PAT)　through　a　two-level　InAs　quantum　dot　(QD)　has　been　successfully　realized　in　experiment　[Phys.　Rev.　Lett.　109,　077401　(2012)].　The　Coulomb　interaction　in　this　device　is　comparable　with　the　energy　difference　between　the　two　energy　levels.　We　theoretically　show　that　the　main　peaks　of　the　experiment　can　be　well　derived　by　our　model　analysis.　Furthermore,　we　find　additional　peaks,　which　were　not　addressed　in　the　InAs　QD　experiment　and　may　be　further　identified　in　experiments.　In　particular,　we　show　that,　to　observe　the　interesting　photon-　induced　excited　state　resonance　in　InAs　QD,　the　Coulomb　interaction　should　be　larger　than　the　THz　photon　frequency.