A specialized water-based feeding machine for deep-sea culture has been designed to address labor-intensive feeding, high feed damage rates, and excessive feed wastage in aquaculture. This is particularly useful in deep-sea cage culture where conventional feeding machines struggle to deliver feed to certain depths. The feeding machine combines the characteristics of deep-sea culture with previous experience in sinking and floating aquaculture cages. Relevant experiments were conducted to determine the suitable feed-to-water weight ratio, water pump power, and the effect of conveying height on the suction rate after conducting experiments with different ratios of feed and water, as well as varying water pump power and different feeding depths. The results showed that the suitable feed-to-water mass ratio is 1:6. As the water pump power increases, the suction rate also increases. When the water pump power remains constant, the suction rate decreases with the increase of the delivery pipe height. With a water pump power of 7.50kW and a lifting height of 46m, the average suction rate of the feeding machine can reach 9.46 kg/min. The delivery depth can reach below 10 meters underwater, meeting the feeding requirements of sinking and floating aquaculture cages in deep water. Therefore, the water-based feeding machine enables underwater feeding in deep-water cage aquaculture, addressing a significant challenge in this field. It offers a cost-effective solution with great potential for widespread application and promotion.