Abstract: Since the research field of calcium carbonate induced by freshwater algae in the plateau is still in the early stage of exploration, this paper focuses on the biological mineralization of freshwater algae on the rock surface under the unique environment of the plateau, and focuses on analyzing the characteristics of sediments induced by algae and their effects on rock mechanical properties. By X-ray diffraction (XRD) test, it is confirmed that the sediment is mainly composed of calcium carbonate precipitation. Furthermore, the microstructure of calcium carbonate was observed by scanning electron microscope (SEM), and the effect of calcium carbonate deposition on compressive strength of rock was analyzed by point load test. The results show that freshwater algae can induce calcium carbonate, but the compressive strength of induced calcium carbonate is weaker than that of attached rocks, and the intrinsic relationship between the microstructure of calcium carbonate deposits and its effect on rock mechanical properties is revealed. As a new geotechnical discovery, calcium carbonate induced by freshwater algae in plateau environment can provide scientific basis for understanding the potential role of biommineralization in rock weathering, sedimentation and geological engineering stability assessment.