Abstract: To study the compression expansion mechanical characteristic of adaptive base, an accurate modeling method based on fiber cord/rubber composite material micromechanics was proposed. The method was based on the precise estimation for material parameters of cord and rubber. The Mooney-Rivilin constitutive model was used to discribe rubber material, and correctness of constitutive model was verified by tension tests. Amending of cord tension modulus was based on bundle cord tension test rule. Based on the methods above, numerical simulation and experimental study of adaptive base compression expansion process were conducted. Results show that the accurate modeling method can simulate the compression expansion characteristics of base effectively. The distributions of stress and strain of cord and rubber materials in base, and their variation laws can be obtained. The study can provide technical support for further research and actual application of adaptive base.