Abstract: To compress value-list index more efficiently，this paper analyzes the disadvantages of the traditional run-length encode approach，and then presents two corresponding improvements，one is to sort the data table to prolong the 0’s and 1’s in the value-list index vectors，the other is to modify the encoding algorithm to compress the 0’s and 1’s at the same time.Experimental results show that the volume of the compressed file when new approach adapted is only 11.83% of that when traditional approach adapted.