Frequent embedded subtree pattern mining is an important data mining problem with broad applications. In this paper, we propose a novel embedded subtree mining algorithm, called PrefixTreeESpan (i.e. Prefix-Treeprojected Embedded-Subtree pattern), which finds a subtree pattern by growing a frequent prefix-tree. Thus, using divide and conquer, mining local length-1 frequent subtree patterns in Prefix-Tree-Projected database recursively will lead to the complete set of frequent patterns. Different from Chopper and XSpanner [4], PrefixTreeESpan does not need a checking process. Our performance study shows that PrefixTreeESpan outperforms Apriori-like algorithm: TreeMiner [6], and pattern-growth algorithms :Chopper , XSpanner .