Aquaculture by means of tanks aboard an aquaculture vessel provides a new way to carry out marine fish culture in the deep sea. To study the influence of the jet on the flow field of the tank aboard an aquaculture vessel, and evaluate the adjustment ability of the jet on the flow field of the tank under the rolling motion, the FLOW-3D is used to study the flow field characteristics of the tank aboard a 3000-ton aquaculture vessel, and to the analysis of the total influent flow rate, the number of water inlets and the amplitude of the roll angle on the velocity and flow uniformity of the fish tank. The results show that with the increase of the total influent flow rate from 110 m³/h to 215 m³/h, the velocity of the tank increases significantly, but the change in the flow uniformity is not significant. With the increase of the number of water inlets from 4 to 16, the velocity in the tank decreases significantly and the flow uniformity increases significantly. For the aquaculture vessel at anchor, the range of rolling period change is small, mostly 5.3-6.4 s. With the rolling angle increasing from 0 ° to 2 °, the maximum velocity of the tank increases from 0.385 m/s to 0.413 m/s, and the flow field changes slightly. When the rolling angle increases from 0 ° to 5 °, the maximum velocity of the tank increases from 0.385 m/s to 0.507 m/s, and the flow field changes greatly. The research shows that for the tank aboard an aquaculture vessel when the number of water inlets is constant, the maximum velocity of the tank is linearly and positively correlated with the total influent flow rate. Therefore, for the fish tank with 4 water inlets, when the total influent flow rate is less than 184 m³ /h, the velocity of the tank is always less than 0.5 m/s, which is suitable for the cultivation of Pseudosciaenacrocea over 1 year old, of which body length is greater than 27 cm. When the velocity of the fish tank is greater than the upper limit of the suitable velocity for fish due to the increase of the total influent flow rate, the velocity of the fish tank can be reduced by increasing the number of water inlets, and the uniformity of the water flow can be increased at the same time. For the aquaculture vessel at anchor, when the amplitude of the rolling angle is less than 2°, the impact of the rolling motion on the flow field of the fish tank is small. At this time, the flow field of the fish tank can be adjusted by changing the total influent flow rate and the number of water inlets. However, when the amplitude of the roll angle is greater than 2°, the rolling motion has a greater impact on the flow field of the fish tank, especially when the amplitude of the roll angle reaches 5°, the regulating effect of the influent jet on the flow field of the fish tank is limited.