Abstract: Coastal aeolian sand is treated as a kind of special soil for its loose structure, poor stability and poor gradation. Cement solidification is a common method for strengthening. However, the influence rule and microscopic mechanism of cement dosage on the mechanical properties of aeolian sand are still unclear. The CD tests under various effective confining pressures (50, 100 and 150 kPa) on aeolian sand solidified by different amounts (0%, 4% and 6%) of cement are carried out using GDS triaxial apparatus. Based on the micrograph of cemented sand and experimental data, the microstructural models for cemented coastal aeolian sand are established using PFC^2D. The mesoscopic numerical analysis of triaxial tests is presented. The results show that the cemented coastal aeolian sand is strain-softened. And the cement dosage makes great contribution to the strength of coastal aeolian sand, but less influence on the volumetric strain. The PFC model with parallel connection can effectively reflect the main mechanical behaviors of cemented coastal aeolian sand. The cement dosage has a significant impact on bond-breaking number, coordination number and displacement field for the cemented coastal aeolian sand.