Fairness　is　a　critical　issue　because　of　some　serious　problems,　such　as　thread　starvation　and　priority　inversion,　it　can　arise　and　render　the　Operating　System　(OS)　scheduler　ineffective　if　no　fair　cache　sharing　which　provided　by　the　hardware.　In　order　to　improve　the　fairness　of　shared　cache　between　threads　in　a　chip　multiprocessor,　a　dynamic　fair　partitioning　policy　of　shared　cache　is　proposed　in　this　paper.　There　are　threads　sharing　cache　and　simulating　that　it　runs　alone　with　a　dedicated　cache.　At　the　end　of　each　time　interval　T,　policy　evaluates　the　metrics　of　threads　on　shared　and　dedicated　cache,　then　repartition　cache　to　improve　the　fairness.　Experimental　data　show　that　the　dynamic　fair　partitioning　policy　of　shared　cache　compared　with　LRU　or　other　partitioning　of　shared　cache　can　effectively　enhance　fairness　and　throughput　has　slightly　increased　for　chip　multiprocessor.　©　2010　IEEE.