In this study, the design variables of the horizontal and longitudinal sections of a metro line are analyzed by setting multiple constraints according to relevant specifications to address the current deficit of a mature appraisal system for assessing the limitations of a design scheme, such as the timeconsuming and inefficient manual adjustment method for metro route alignment and slope adjustment. Additionally, an objective function with penalty terms for limit violation tolerance and violation of specifications is established. Moreover, a mathematical analysis model based on particle swarm optimization algorithm is proposed for metro alignment and slope adjustment, following which an intelligent design system that is applicable to rectangular, horseshoeshaped, circular, and other types of tunnel section is developed. For validation and comparison, the conventional manual design and the newlydeveloped intelligent design of the alignment and slope adjustment are tested for a rightline tunnel in Changsha metro line 4. The results demonstrate the improved design of the intelligent system rationalizes the selection of the alignment parameters and optimizes the limit invasion to achieve significant reduction in labor costs. Moreover, the proposed intelligent design system is reliable and highly efficient.