Electron　transport　characteristics　through　a　system　consisting　of　a　series　of　triangular　quantum　dot　rings　are　studied　utilizing　the　non-equilibrium　Green＇s　function.　In　the　presence　of　a　magnetic　field,　an　additional　anti-resonance　point　occurs　in　the　conductance　spectrum.　As　the　number　of　triangular　quantum　dot　rings　increases,　two　anti-resonance　points　evolve　into　two　well-defined　insulating　bands.　The　insulating　band　disappears　as　the　magnetic　flux　takes　an　appropriate　value,　and　therefore,　an　effective　magnetically-controlled　quantum　switch　can　be　achieved.　If　a　Zeeman　magnetic　field　is　introduced,　a　spin-polarized　window　(SPW)　can　be　formed,　suggesting　a　physical　scheme　of　a　spin　filtering.　As　the　intradot　Coulomb　interactions　are　taken　into　consideration,　more　SPWs　can　be　obtained.　This　work　sheds　lights　onto　the　design　of　future　quantum　devices.