As　a　research　focus　within　the　field　of　array　signal　processing,　multi-source　direction-of-arrival　(DOA)　estimation　in　enclosed　environments　has　been　paid　much　attention.　Contaminated　by　reverberation,　noise,　and　inter-source　interference,　DOA　estimation　become　challenging.　Hence　it　is　essential　to　identify　time-frequency　(TF)　points　dominated　by　only　one　source　to　alleviate　these　issues.　This　paper　proposes　a　TF　point　selection　method　for　DOA　estimation　based　on　the　first-order　relative　harmonic　coefficient　(RHC).　This　is　first　analyzed　on　the　“point”　level　from　two　perspective,　and　we　design　an　adaptive　single-source　dominant　zone　(SSDZ)　detection　method.　Subsequently,　the　relationship　between　first-　and　zero-order　RHC　magnitudes　of　different　types　of　TF　points　is　explored,　and　we　develop　a　simple　but　useful　rule　to　further　select　TF　points　in　the　detected　SSDZs.　Finally,　we　adopt　two-dimensional　(2-D)　kernel　density　estimation　(KDE)　and　peak　search　to　estimate　the　DOAs　of　sources　after　calculating　the　angles　of　the　detected　TF　points.　The　effectiveness　and　robustness　of　the　proposed　method　are　verified　and　compared　with　the　reference　methods　through　experiments　with　both　the　simulated　and　real-world　recordings.　IEEE