DNA sequences that are near to splice sites have remarkable conservativeness, and many researchers have contributed to the predic-tion of splice site. In order to mine the underlying biological knowledge, we analyze the conservativeness of DNA splice site adjacent sequences by clustering. Firstly, we propose a kind of DNA splice site sequences clustering method which is based on DBSCAN, and use four kinds of dissimilarity calculating methods. Then, we analyze the conservative feature of the clustering results and the experimen-tal data set.