Abstract: Incremental sequence pattern mining algorithm is one of the hot research issues in the field of sequence pattern mining.In this paper,an incremental mining algorithm for sequence pattern named IU_DB is proposed,which deals with the growth of sequence database.IU_DB algorithm divides the newly emerged frequent sequences generated by database updating into two categories and mines them respectively.The results of previous mining are applied to improve the efficiency of the mining.Final experimental results show that the IU_DB algorithm is correct and efficient.Furthermore,when new datasets is small and threshold of support is low,IU_DB algorithm performs better.