对导管架海洋平台优化设计中的应力约束、桩基横向承载力约束和构件长细比约束进行了分析 ,论证了应力约束取构件截面最大 Mises应力、桩基横向承载力约束取桩顶侧位移或最大抗力比和构件长细比约束取受压构件长细比许用值作为约束的合理性。提出了精细一维搜索算法 ,并用此法求得构件截面 Mises应力最大值。 Stress restraint, lateral bearing capacity constraint of pile foundation and slenderness ratio of member in offshore platform are analyzed. The maximum Mises stress of cross-section of member is obtained, and the top lateral displacement of pile is constrained by the lateral bearing capacity of pile. Or the maximum resistance ratio and the slenderness ratio of the component to the allowable value of the slenderness ratio of the compression component as the rationality of constraint. A precise one-dimensional search algorithm is proposed, and the maximum value of Mises stress of the member section is obtained by this method.