Replacing traditional cement⁃based materials with oyster shell powder can effectively reduce building material costs while achieving the utilization of oyster shell waste.With oyster shell powder as the admixture of ordinary Portland cement，the effects of different doping amount and different grinding methods on the strength and stability of cement mortar were discussed，and the appropriate addition amount of oyster powder was determined.XRD，SEM and EDS analysis methods were used to characterize the changes in the structure and performance of the cementitious test block under different dosage.The results showed that the strength of cement mortar was obviously affected by the ball milling method of oyster shell，and the strength of the cementitious material mixed with wet ball milling oyster shell powder was higher than that of the corresponding sample mixed with dry ball milling.When the addition amount of oyster shell powder was 5%，the compressive strength and flexural strength of the sample reached 49.2 MPa and 7.55 MPa，respectively，which were significantly higher than the blank sample without addition.After pre curing and boiling，the surface of the samples prepared by the stability test was smooth，without cracks，and the volume had no obvious expansion or contraction，indicating that the stability of the gelling material doped with oyster shell powder was good.Microstructure characterization results showed that oyster shell powder existed independently in cement cementitious materials and mainly played an inert filling role.It was feasible to partially replace cement-based materials with oyster shell micro powder，which could improve the comprehensive performance of cement-based materials，save material costs，reduce environmental pollution and have good application prospects.