The microenvironment formed by photosynthesis of submerged macrophytes is favourable for the formation of CaCO₃-P co-precipitation of calcium and phosphorus in the water column. However, the ability of calcium and phosphorus to form CaCO₃-P co-precipitation in the water column varies under different water environmental factors. In this study, Potamogeton crispus was used to investigate the impacts of different calcium concentrations (0, 20, 35, 50, and 65 mg/L), alkalinity (0, 100, 200, 300, and 400 mg/L CaCO₃), phosphorus concentrations (0, 0.1, 0.2, 0.3, and 0.4 mg/L), and temperatures (11, 14, 17, 20℃) on the ability of P. crispus to reduce phosphorus and CaCO₃-P co-precipitation. By analyzing the trend of the saturation index of the culture solution of the no-plant control group, this study revealed the law of plant-mediated CaCO₃-P occurrence, and provided a theoretical basis for the selection of submerged macrophytes in the ecological restoration of lakes. The results showed that the total phosphorus (TP) and soluble reactive phosphorus (SRP) concentrations decreased significantly in the P. crispus culture group. There were significant differences between different treatment groups. As calcium concentration increased, TP and SRP concentrations decreased in all treatment groups, with a decreasing rate depending on the addition of calcium. In contrast, there were no significant changes in TP and SRP concentrations in the no P. crispus culture group. This suggested that P. crispus enhanced phosphorus removal. In all the treatment groups, CaCO₃-P co-precipitation increased with increasing alkalinity, with maximum CaCO₃-P co-precipitation at an alkalinity concentration of 400 mg/L CaCO₃. This suggested that P. crispus was more conducive to CaCO₃-P co-precipitation in an alkaline water environment. Co-precipitation was highest at moderate phosphorus levels (0.2 mg/L), with an average of 23.12 mg co-precipitation per day for each P. crispus. The experiments verified that the natural water body phosphorus concentration has limited difference on the production of CaCO₃-P co-precipitation in the leaves of P. crispus. The co-precipitation was highest at the medium temperature level (17℃), with an average of 16.61 mg co-precipitation per day for each P. crispus. This suggested that there was not much difference in the production of co-precipitation by P. crispus at the appropriate temperatures. These results indicated that alkalinity has a greater effect on CaCO₃-P co-precipitation in P. crispus compared with phosphorus concentration and temperature. Under the same water environment, the calcium carbonate saturation indices (calcite and aragonite saturation indices) of the control group without P. crispus were greater than 0, indicating a crystallisation tendency. However, no precipitation was produced during the experimental period, whereas the treatment group with added P. crispus produced unequal amounts of CaCO₃-P co-precipitation, which suggested that submerged macrophytes can reduce phosphorus by co-precipitation. This study can potentially provide theoretical support for water management of lake eutrophication.