Abstract: Abstract: Net enclosure aquaculture is a newly developed eco-friendly marine aquaculture method and has been applied extensively in China because of the advantages of large water body, wide space for fish activities, closer to nature culture environment and closer to wild culture objects. Pile-type and floating-rope-type are two main construction types of enclosure engineering, and the pile-type is more preferable owing to its higher performance in withstanding harsh ocean environment. The pile-type aquaculture engineering consists of net panel system and pile system configured in mono or multi rows. In practice, the overturn and breakage of the piles have occurred and lead to the escape of cultured fishes, resulting in great economic loss. In order to solve these problems and improve the stability and safety of piles, the mechanical characteristics of piles in marine dynamic environment were analyzed in this study, and the pile-type aquaculture site located at Taohua island, Zhoushan was chosen as the study case. The subgrade reaction method, representing the soil surrounding of the pile by a series of discrete horizontal springs was adopted to investigate the effects of water depth, current velocity, wave height and combined action of wave and current, together with the embedded depth on the dynamic response of piles. The results showed that the maximum displacement was found at the top of the pile and increased with the increase of current velocity, wave height and water depth, and decreased with the increase of embedded depth. The positive and negative bending moment in the sides of the vertical line of zero bending moment increased first and then decreased along the pile, showing a shape of symmetrical S. The maximum bending moment was found about 2 m underneath the sea bed and exhibited a similar dynamic tendency to that of the maximum lateral deflection. As for the case of pure current, the piles kept stable and safety at the current velocity of 0.8, 1.0, 1.2 and 1.5 m/s. However, it could be damaged when the wave height exceeded 5 m or in the combined action of wave height of 3.0 m and current velocity of 1.0 m/s. For the engineering case in this study, the embedded depth should be larger than 17 m when the wave height of 5 m was considered as the lateral loading. In addition, a ratio of the length above the sea bed surface and embedded in the sea bed of the pile not more than 0.8 was advisable. Filed observation of the piles lateral deflection and stress force should be monitored in a long period so as to improve the analytical method specially used for net enclosure engineering. The results can provide guidance for the net enclosure design and construction.