Abstract: Although Apriori algorithm uses cut-technology when it generate item sets of candidates，it has to scan the entire database while scanning the transaction database each time.The scanning speed is very slow for its large amount of data.The Apriori-sort algorithm is improved from the Apriori algorithm.Its basic idea is to transform a transaction database into a transaction degree database，and sort the transaction-degree database.When the Apriori-sort algorithm searches the frequent item sets，it only scans the transactions in the database Dd that appeases d（Ck）≦d（Ti）.It scans the database with an effective cut.Therefore the Apriori-sort algorithm’s computing time is very fast.The results of simulation experiments for the Apriori-sort algorithm and the Apriori algorithm show the new algorithm’s efficiency.