This study aims to identify suitable density of suspended trays and care regime, which was conducted from February to November 2022 at Tay Van Boi, Lan Ha Bay, Cat Ba, Cat Hai - Hai Phong to improve growth, survival rates and helping to shorten the time for snout otter clam grow-out culture. The experiment was carried out with 3 treatments: Densities of 4, 8 and 12 trays/4 m2 combined with 3 care regimes during grow-out culture. The results showed that densities of 4 and 8 trays/4 m2 were higher growth than the remaining treatment, specifically length was from 32.9 - 36.8 mm and survival rate was over 84%, with a significant difference, compared to a density of 12 trays/4 m2 with 3 different care regimes. The results show that to increase productivity and reduce production costs and care time, a density of 8 trays/4 m2 with 3 care regimes/a culturing period should be chosen. The study has also propounded disease prevention and treatment measures for the Snout otter clam to help control the disease well and proposed solutions on farming techniques that contribute to high and sustainable economic efficiency.