Abstract: In order to reduce the cost of crude oil storage devices during the development of marginal oil fields, an underwater oil storage tank scheme was proposed. In this paper, ABAQUS finite element software is used to analyze the overall structural strength of the tank. On this basis, the sensitivity analysis of the main parameters of the tank reinforcement member is carried out. Finally, a structural strengthening scheme for subsea oil storage tank that not only meets the strength requirements but also effectively improves the economy is determined. The research results have certain reference significance for the development of subsea oil storage tank schemes in marginal oil fields.