Metalenses　have　attracted　a　great　deal　of　research　interests　due　to　the　property　of　light　controllability.　How　to　enhance　the　focusing　effect　of　metalens　has　always　been　a　key　problem　that　many　researchers　have　been　working　on.　In　this　paper,　we　propose　a　novel　sub-dimensional　resonance-based　optimization　method　for　dielectric　metalens　with　golden　angle　spiral　arrays.　The　waveguiding　effect　is　first　applied　to　the　initial　design　of　the　quasi-periodic　metalens　through　the　defined　equivalent　period.　Then　the　genetic　algorithm　is　improved　for　adjusting　the　sub-dimensional　structure　of　the　initial　metalens.　The　optimization　results　show　that　the　peak　intensity　of　central　hot　spot　increases　by　32　%　while　keeping　the　full　width　at　half　maximum　(FWHM)　almost　unchanged.　At　the　same　time,　the　field　intensity　of　side　lobes　around　the　hot　spot　decreases,　which　means　that　a　potential　way　for　high-contrast　imaging　is　provided.　©　2024