The study was conducted in May - June 2018 in the water bodies of the mangrove ecosystem of Kuala Langsa Village with the aim of knowing survival, growth conditions, growth characteristics and environmental factors that affect the growth of Portunus pelagicus crabs while in the mangrove ecosystem. The method used was a one-factor completely randomized design with 4 treatment levels, where environmental parameters were collected in situ and ex situ with statistical analysis using ANOVA, orthogonal polynomials and PCA. The results of the study showed that the pH of the water ranged from 7.40 - 7.57, salinity 26.17 - 28.87‰, DO 4.92 - 5.88 mg/L, temperature 29.89 - 30.71°C, TDS 338.54 - 358.64 mg/L, pH H2O 4.43 - 4.51, pH KCL 2.96 - 3.59, C-organic 3.03 - 6.52%, N-total 0.19 - 0.26%, C/N 16.09 - 26.10 and P-available 19.12 - 21.52 ppm. In addition, survival ranged from 41.60 - 88.80%, absolute growth of carapace 13.80 - 30.80 cm, relative carapace 0.56 - 1.02 cm, absolute weight 16.10 - 18.50 gr, daily length 0.46 - 0.65 cm, daily width 0.36 - 0.59 cm and daily weight 0.72 - 0.93 gr. PCA analysis showed that the growth characteristics of P. pelagicus crabs in the mangrove ecosystem waters of Kuala Langsa Village were absolute length growth and daily length growth, while environmental factors that influenced their growth were C/N sediment parameters, C-organic sediments and water temperature. Kajian dilakukan pada bulan Mei – Juni 2018 di badan perairan ekosistem mangrove Desa Kuala Langsa dengan tujuan untuk mengetahui sintasan, kondisi pertumbuhan, pertumbuhan penciri dan faktor lingkungan yang mempengaruhi pertumbuhan kepiting Portunus pelagicus saat berada di ekosistem mangrove. Metode yang digunakan adalah rancangan acak lengkap satu faktor dengan 4 taraf perlakuan, dimana parameter lingkungan dikumpulkan secara in situ dan ex situ dengan analisis statistik yang digunakan adalah ANOVA, polinomial ortogonal dan PCA. Hasil kajian memperlihatkan bahwa pH air berkisar antara 7.40 - 7.57, salinitas 26.17 - 28.87‰, DO 4.92 - 5.88 mg/L, suhu 29.89 - 30.71°C, TDS 338.54 - 358.64 mg/L, pH H2O 4.43 - 4.51, pH KCL 2.96 - 3.59, C-organik 3.03 - 6.52%, N-total 0.19 - 0.26%, C/N 16.09 - 26.10 dan P-tersedia 19.12 - 21.52 ppm. Selain itu, untuk sintasan berkisar antara 41.60 - 88.80%, pertumbuhan mutlak karapas 13.80 - 30.80 cm, nisbi karapas 0.56 - 1.02 cm, berat mutlak 16.10 - 18.50 gr, panjang harian 0.46 - 0.65 cm, lebar harian 0.36 - 0.59 cm dan berat harian 0.72 - 0.93 gr. Untuk analisis PCA menunjukkan bahwa penciri pertumbuhan kepiting P. pelagicus di perairan ekosistem mangrove Desa Kuala Langsa adalah pertumbuhan panjang mutlak dan pertumbuhan panjang harian, sedangkan faktor lingkungan yang mempengaruhi pertumbuhannya adalah parameter C/N sedimen, C-organik sedimen dan suhu air.