The　problem　of　tracking　foreground　objects　in　a　video　sequence　with　moving　background　remains　challenging.　In　this　paper,　we　propose　the　Fast　Two-Cycle　level　set　method　with　Narrow　band　Background　(FTCNB)　to　automatically　extract　the　foreground　objects　in　such　video　sequences.　The　level　set　curve　evolution　process　consists　of　two　successive　cycles:　one　cycle　for　data　dependent　term　and　a　second　cycle　for　smoothness　regularization.　The　curve　evolution　is　implemented　by　computing　the　signs　of　region　competition　terms　on　two　linked　lists　of　contour　pixels　rather　than　solving　any　Partial　Differential　Equations　(PDEs).　Maximum　A　Posterior　(MAP)　optimization　is　applied　in　the　FTCNB　method　for　curve　refinement　with　the　assistance　of　optical　flows.　The　comparison　with　other　level　set　methods　demonstrate　the　tracking　accuracy　of　our　method.　The　tracking　speed　of　the　proposed　method　also　outperforms　the　traditional　level　set　methods.