Improving　residents＇　travel　efficiency　and　reducing　carbon　emissions　from　travel　are　the　key　issues　for　sustainable　development　of　urban　transportation.　This　study　first　employed　a　circuity　index　to　measure　the　path　efficiency　of　residents＇　trips　based　on　2015　survey　data　in　Guangzhou　and　developed　a　generalized　additive　model　(GAM)　to　investigate　the　relationship　between　the　path　efficiency　and　travel　distance　for　different　purposes　of　trip　and　different　travel　modes.　On　this　basis,　it　further　evaluated　the　time　efficiency　of　different　travel　modes　for　each　trip.　The　results　showed　that　there　is　a　complex　and　nonlinear　relationship　between　the　path　efficiency　and　travel　distance,　which　differs　between　different　purposes　of　trips　and　different　travel　modes.　In　general,　trips　by　non-motorized　transport　have　a　lower　circuity　index　and　higher　path　efficiency　than　those　by　cars　or　public　transport.　Moreover,　non-motorized　transport　is　the　time-efficiency　optimal　mode　for　almost　half　of　the　trips,　especially　for　daily　shopping　trips.　However,　people　prefer　to　choose　public　transport　on　their　trips　even　though　public　transport　is　not　the　time-efficiency　optimal　mode　for　these　trips.　Generally,　only　about　half　of　the　residents　chose　the　time-efficiency　optimal　mode　for　their　trips.　Those　who　did　not　choose　the　time-efficiency　optimal　mode　tended　to　choose　the　modes　with　higher　carbon-intensity.　The　conclusions　of　this　study　indicate　that　for　improving　travel　efficiency　and　reducing　carbon　emissions　from　transport,　more　efforts　should　be　focused　on　the　non-motorized　travel　environment　and　developing　relevant　policies　to　encourage　more　walking　and　cycling.