There is an increasing need for an XML query en- gine that not only searches for exact matches to a query but also returns \query-like" structures. We have designed and developed XFinder, an efficient top K tree pattern query evaluation system, which reduces the problem of approximate tree structural matching to a simpler problem of subsequence matching. How- ever, since not all subsequences correspond to valid tree structures, it is expensive to enumerate common sub- sequences between XML data and query and then fil- ter the invalid ones. XFinder addresses this challenge by detecting and pruning structurally irrelevant subse- quence matches as early as possible. Experiments show the efficiency of XFinder on various data and query sets.