Abstract: Based on set theory, the similarity and disparity indices among plant distribution regions were defined with the Jaccard’s similarity index. The similarity among six mangrove distribution regions in the world was analysed. The results showed that the region most similar to the eastern coast of Africa was the coast of Oceania, the region most similar to the coast of Asia and the eastern Pacific Archipelago was the coast of Oceania, the region most similar to the western coast of America was the western coast of Africa, the region most similar to the western coast of Africa was the eastern coast of America. By cluster analysis of the six mangrove distribution regions, the western coast of Africa and the eastern coast of America, the coast of Asia and eastern Pacific Archipelago and the coast of Oceania, were merged into two large regions respectively. The six mangrove distribution regions were further merged into two large regions which were consistent with the east central group and the west central group.

Key words: Mangrove, Region, Similarity, Disparity