Workflow　scheduling　with　the　objective　of　time-cost　optimization　is　a　fundamental　problem　in　grids　and　generally　the　problem　is　NP-hard.　In　this　paper,　a　novel　heuristics　called　SL　(Segment　Level)　for　workflows　represented　by　DAG　(Directed　Acyclic　Graph)　is　proposed.　Considering　the　parallel　and　synchronization　properties,　the　workflow　application　is　divided　into　segments,　and　the　workflow　deadline　is　transformed　into　the　time　intervals　and　appointed　to　different　segments.　The　floating　time　is　prorated　to　each　segment　to　enlarge　cost-time　duration,　and　a　dynamic　programming　method　is　implemented　to　optimize　cost　for　each　segment.　By　comparing　SL　with　MCP　(Minimum　Critical　Path),　DTL(Deadline　Top　Level),　DBL(Deadline　Bottom　Level),　the　heuristics＇　efficiency　is　verified　by　experimental　results.