对白云石和大理石的成分、表面和粒径进行测定，并对两种粉体填充高密度聚乙烯（HDPE）复合材料的力学性能进行比较，研究白云石替代传统大理石型碳酸钙制备复合材料的可行性。结果表明：在相同粉碎条件下，得到的白云石粉体较大理石粉体具有更小的颗粒度和更窄的颗粒度分布，颗粒形态更加规整；白云石/HDPE复合材料的冲击强度（18.12 kJ/m²）高于大理石/HDPF复合材料的冲击强度（8.60 kJ/m²）。通过傅里叶红外光谱仪（FTIR）、扫描电子显微镜（SEM）、万能力学试验机进一步考察不同改性剂对白云石的改性效果以及改性白云石/HDPE复合材料力学性能的影响。结果表明：采用硬脂酸-偶联剂协同改性处理，白云石与HDPE基体的相容性得到改善，复合材料的冲击强度、弯曲强度和拉伸强度相比未改性白云石复合材料分别提高71.08%、7.40%和6.43%。

To study the feasibility of dolomite replacing traditional marble calcium carbonate in the preparation of composites, the composition, surface and particle size of dolomite and marble were determined, and the mechanical properties of high-density polyethylene (HDPE) filled with two powders were compared. The results showed that the dolomite powder had smaller particle size, narrower particle size distribution and more regular particle shape than marble powder under the same crushing conditions. The impact strength of dolomite/HDPE composites (18.12 kJ/m²) was higher than that of marble/HDPF composites (8.60 kJ/m²). The modification effects of different modifiers on dolomite and the mechanical properties of modified dolomite/HDPE composites were investigated by FTIR, SEM and universal mechanical testing machine. The results showed that the compatibility between dolomite and HDPE matrix was improved when the stearic acid and coupling agent were used, and the impact strength, flexural strength and tensile strength of the composites increased by 71.08%, 7.40% and 6.43%, respectively, compared with the unmodified dolomite composites.