This research was conducted to test the mangrove crab of Sesarmidae family as bio-indicator to assess health status of mangrove ecosystem in Youtefa Bay of Jayapura. Conducted since March-August 2017. Conducted in 3 stations namely St. Enggros, St.Tobati, and St. Nafri. Using the quadratic transect method (1x 1 m) and the quadratic transect (10 x 10 m). Data were analyzed using index of diversity, dominance, evenness, abundance, density, simple linear regression and test criteria of indicator species. The result of the research found the level of mangrove diversity in Enggros Station with the value of index 1.9 then Tobati and Nafri Station of 1, 4 with abundant diversity level. The density of mangroves in the three stations is obtained by Enggors: 1455.6 trees / Ha, Naftri: 1477.8 trees / Ha, and Tobati 1033,5 trees / ha with moderate density categories and good ecosystem health conditions. The biological criteria indicator test shows that the Sesarmidae crab meets the six criteria of the indicator species, so that it can be designated as a species indicator of the health status of the ecosystem.Keywords: Indicator, Crab, Sesarmidae, Mangrove, Youtefa, Jayapura. AbstrakPenelitian ini dilakukan untuk menguji kepiting mangrove famili Sesarmidae sebagai bio-indikator untuk menilai status kesehatan ekosistem mangrove di Teluk Youtefa Jayapura. Dilakukan sejak bulan Maret sampai dengan Agustus 2017. Dilakukan di 3 stasiun yakni di St. Enggros, St.Tobati, dan St. Nafri dengan metode transek kuadrat (1x 1 m) dan transek kuadrat (10 x 10 m). Data dianalisis menggunakan indeks keanekaragaman, dominansi, kemerataan, kelimpahan, kerapatan, regresi linear sederhana dan uji kritaria spesies indikator. Hasil penelitian menemukan tingkat keanekaragaman mangrove di Stasiun Enggros dengan nilai indeks 1,9 serta Stasiun Tobati dan Nafri sebesar 1, 4 dengan tingkat keanekaragaman sedang melimpah. Kerapatan mangrove pada ketiga stasiun diperoleh Enggors: 1455.6 pohon/Ha, Naftri: 1477.8 pohon/Ha, dan Tobati 1033,5 pohon/ha dengan katagori kerapatan sedang dan kondisi kesehatan ekosistem baik. Uji kriteria biologi indikator menunjukan kepiting Sesarmidae memenuhi enam kriteria spesies indikator, sehingga dapat ditetapkan sebagai spesies indikator status kesehatan ekosistem .