With　the　help　of　a　continuation　theorem　based　on　Gaines　and　Mawhin＇s　coincidence　degree,　several　verifiable　criteria　are　established　for　the　global　existence　of　positive　periodic　solutions　of　a　class　of　non-autonomous　single　species　population　model　with　delays　(both　state-dependent　delays　and　continuous　delays)　and　feedback　control.　After　that,　by　constructing　a　suitable　Lyapunov　functional,　sufficient　conditions　which　guarantee　the　existence　of　a　unique　globally　asymptotic　stable　positive　periodic　solution　of　a　kind　of　nonlinear　feedback　control　ecosystem　are　obtained.　Our　results　extend　and　improve　the　existing　results,　and　have　further　applications　in　population　dynamics.　©　Springer-Verlag　2005.