为解决现有民用飞机机载系统设计流程难以在设计前期发现顶层设计偏差的问题，对现有的瀑布式设计流程、V形设计流程及螺旋形设计流程进行了详细分析及对比，总结了各自在系统设计中的优势和局限性，提出采用螺旋形流程对V形流程进行改造的设计方法。该方法强调在设计前期采用模型对设计结果进行充分仿真验证，发现前期设计偏差，进行反复迭代，完善设计；在后期系统综合各阶段进行充分的综合测试验证，并根据结果对系统设计进行修正，确保系统满足前期各项需求。经详细分析表明，该流程集中了传统设计方法的优点，能在设计初期发现各种问题，具有很好的可行性。

It is difficult to discover the top-level design deviation for the complicated system of civil aircraft ahead of schedule based on traditional design procedure.To solve the problem，we analyzed the cascade design procedure，V-shaped procedure and spiral procedure in detail，summarized their advantages and limits，and proposed a method using the spiral procedure to optimize the V-shaped procedure.During early design stage，this method focuses on simulation and verification to the system scheme based on model，thus can discover the early designing error.Iterations are made to make the scheme complete.In latter system integration，test and validation are carried out，and the design is modified based on the test result，thus to make the system satisfy all the requirements.Detailed analysis shows that this is a method which has all the advantages of the traditional procedure，it is a feasible method that can discover the design error ahead of schedule.