Abstract: Based on the chaos theory, the characteristics of chaos in nonlinear dynamic systems were applied to analysis and research on the time series of the settlement of highway subgrade. On the basis of phase space reconstruction, C-C method was used to find the embedded delay and the embedding window, and G-P method was applied to figure out the embedding dimension. Small data method was applied to calculate the maximum Lyapunov exponent of the time series of highway settlement, the analysis of chaotic characteristics was conducted. The results demonstrated that the accumulated settlement was in accordance with the chaotic characteristic. Finally, the short term settlement was predicted successfully.