[Purposes] This work aims to study the influence of the compaction difference between the upper and lower layers of double-layer cement stabilized macadam base on the performance of the base. [Methods] Firstly, the specimens with different water to cement ratio and cement slurry dosage between layers were subjected to direct shear test and tensile test to obtain the optimum water to cement ratio and cement content. On this basis, the effects of the compaction difference between layers on the unconfined compressive strength, flexural tensile strength and fatigue life of double-layer water stabilized macadam were studied. Finally, ABAQUS was used to simulate the road surface deflection of the actual pavement with different compactness of the upper and lower layers, and the bending tensile stress at the bottom of each structure layer. [Findings] The optimum cement slurry dosage and water to cement ratio between water stabilized macadam layers were 0.311 g/cm2 and 1∶1.5, respectively. Improving the overall compactness of the base and reducing the compactness difference between the upper and lower layers of the base couldimprove the overall mechanical strength and fatigue performance of the cement stabilized macadam base, reduce the road surface deflection and improve the fatigue life of the base. [Conclusions] Reducing the compaction difference between the upper and lower layers of water stabilized macadam base couldsignificantly improve the strength and durability of the base.