We also place emphasis on research of apriori and fp - growth algorithm and compare the performance of two algorithms . secondly , we do research on concepts of structured and nonstructured data , actual state and problems of tree structure mining , and freetreeminer algorithm theory . we also study canonical form and pre - processing technologies of free - tree , concepts and properties of closed and maximal tree , and pruning , growing and mining of tree structure 其次,研究了結構化與非結構化數據的基本概念、樹結構挖掘的研究現狀、現有樹結構挖掘技術存在的問題、 freetreeminer算法及其基本思想,重點研究了free樹的規(guī)范化和預處理技術、封閉頻繁子樹和最大頻繁子樹的概念和性質、樹結構的剪枝和生長技術、樹結構的挖掘技術。