在套管柱设计领域中引进了分支定界法优化理论．阐述了分支定界优化设计石油套管的基本思想．并简单介绍了利用该方法开发出的一套套管柱优化设计软件．与常规设计法相比，用该优化软件设计出的套管柱，用最低费用套管优化组合设计能节约费用２３．６４％，重量降低０．２４％．用最轻重量套管优化组合设计可节约费用１８．５５％，重量降低１９．１１％． The theory of branch and bound optimization is introduced in the field of casing string design. Described the basic idea of ​​bifurcating, demarcating and optimizing oil casing design. And a brief introduction to the use of this method developed a casing string optimization design software. Compared with the conventional design method, the casing string designed by this optimization software can save 23.64% of the cost and reduce the weight by 0.24% with the optimized combination design of the lowest cost casing. With the lightest weight casing design optimization combination can save 18.55% cost, weight reduction of 19.11%.