Abstract:The width of highway is an important factor for the stress state of subgrade,and the settlement distribution of subgrade changes with the width of highway. According to the observed data of settlement in Xinxiang—Zhenzhou section of Beijing—Zhuhai Highway,the settlement distribution along the width of narrow subgrade was of a parabolic curve,but the distribution of wide subgrade was saddle-shaped. The finite element method was applied to the analysis of the influence of width on the settlement distribution by employing the Duncan-Chang constitutional model. Numerical results indicated that the distance between the maximum settlement point and the center of subgrade was proportional to the width of half-subgrade. When widths of the half-subgrade increased from 20 m to 66 m,the ratios of distance between the maximum settlement point and the centre of subgrade to the width of half-subgrade increased from 0.0 to 0.6.