The invention discloses a reinforcing method of the floatability of pyrrhotite in a high-calcium water body. In the flotation process of the pyrrhotite in the high-calcium water body, calcium ions in ore pulp are subjected to complexing through organic acid complexing agent such as oxalic acid and citric acid, a hydrophillic layer of the pyrrhotite is cleaned, and then copper sulfate is adopted for activation. Through the method, the floatability of the pyrrhotite can be effectively improved, and the method can be applied to magnetite desulfurization and the like which relate to the pyrrhotite floatability commercial run. When magnetic iron concentrate with the sulfur content being 0.8-1.5% is processed, through the steps of one time of roughing, two times of concentration and two times of scavenging, the sulfur removal rate can be 75-86%, and the iron loss ratio is no less than 5%. The floatability of the pyrrhotite in the high-calcium water body is improved through the method, and the magnetite flotation desulfurization index can be increased under the condition that an original technological process is not changed.