After　a　discussion　of　the　task　allocation　problem　in　multi-core　processor　based　parallel　system,　this　paper　gives　the　task　allocation　model,　and　proposes　an　iteration-based　heuristic　algorithm,　which　is　composed　of　two　rounds　of　operations,　in　which　the　processes　are　assigned　to　processing　nodes　in　the　first　round　and　threads　in　process　are　assigned　to　processor　cores　in　the　second　round　respectively.　Each　round　of　operation　partitions　the　Task　Interaction　Graph　by　iterations　with　backtracking.　Evaluation　result　shows　that　the　algorithm　can　find　near-optimal　solutions　in　reasonable　time,　and　behaves　better　than　genetic　algorithm　when　the　number　of　threads　increases,　since　it　can　find　solutions　in　much　less　time　than　genetic　algorithm.