This study was conducted to analyze the diversity of Brachyuran crab with square transect methods. This research was conducted from March to June 2014 on Tikus Island, Pari Island, Seribu Island. Square transect was applied for western (T1& T2), north (T3& T4), east (T5&T6) and south (T7&T8) Tikus Island. The results showed that there were 34 species in total which belong to 11 families found in Portunidae, Majidae, Galenidae, Dromiidae, Calappidae, Ocypodidae, Grapsidae, Porcellanidae,

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... halmidae, Xanthidae, and Pilumnidae. The eastern part of Tikus Island had the highest values diversity of crab (H'=2,609), meanwhile, the southern part had a highest dominance index (C=0,117), and the highest Pielou evennes index was in northern part (J=0,923). The varies type of substrate was an important factor for the diversity of crabs. Overall, Tikus Island still had a high diversity of crabs and Xanthidae was the highest dominance crabs.