Structural join is the core operation in XML query processing, and catches the research community抯 attention. Efficient algorithm is the key of efficient query processing. There have been a number of algorithms proposed for structural join, and most of them are based on one of the following assumptions: the input element sets either have indexes or are ordered. When these assumptions are not true, the performance of these algorithms will become very bad due to the cost of sorting input sets or building index on the fly. Motivated by this observation, a structural join algorithm based on range partitioning is proposed in this paper. Based on the idea of task decomposition, this algorithm takes advantage of the region numbering scheme to partition the input sets. The procedure of the algorithm is described in detail, and its I/O complexity is analyzed. The results of the extensive experiments show that this algorithm has good performance and is superior to the existing sort-merge algorithms when the input data are not sorted or indexed. It can provide query plans with more choices.