Shear　walls　of　cold-formed　steel　(CFS)　with　high　aspect　ratios　could　be　used　in　buildings　with　large　openings　such　as　doors　and　windows.　However,　the　performance　of　CFS　shear　walls　with　high　aspect　ratios　remains　unclear　due　to　limited　test　data.　This　research　aimed　to　explore　the　mechanic　performance　and　strength　reduction　factor　of　CFS　shear　walls　with　high　aspect　ratios　through　an　experimental　study.　Five　full-scale　specimens　were　tested　under　monotonic　loading,　and　the　failure　mechanism,　bearing　capacity,　stiffness,　ductility,　and　energy　dissipation　of　the　specimens　were　obtained.　The　test　results　indicated　that　shear　walls　with　small　aspect　ratios　typically　fail　as　a　result　of　connection　damage　to　horizontal　seams　and　corners,　whilst　shear　walls　with　high　aspect　ratios　commonly　buckle　at　both　the　end　stud　and　bottom　track.　As　the　aspect　ratio　increased,　the　initial　stiffness　and　capacity　decreased,　while　the　energy　dissipation　per　unit　length　increased　due　to　greater　flexibility.　Ultimately,　this　study　proposes　a　more　reasonable　design　formula　for　strength　reduction　factors　based　upon　a　regression　analysis　of　the　test　data.　This　will　facilitate　a　more　sustainable　design　approach,　and　fulfills　current　standards　in　engineering　practice.