To study the effect of inorganic electrolyte solution on graphite flotation, 19 kinds of inorganic electrolytes, including nitrate, chloride and sulfate were selected as experimental electrolytes. The flotation experiment was carried out on graphite and the contact angle and surface potential of the interaction between inorganic electrolyte solution and graphite were studied. The results show that flotation effect and flotation rate of the three ion valence inorganic electrolytes follow the order: nitrate < chloride < sulfate and univalent < bivalent < trivalent (except Ba(NO3)2 and Pb(NO3)2). When the ion valence are the same, the larger the ion atomic number, the better effect on graphite flotation. Cations in inorganic electrolyte solutions are the main factors affecting mineral flotation. When the cationic type and concentration are the same, different flotation effects are attributed to different anions. For low ion valence inorganic electrolyte solution with weak foaming effect, a certain dose of frother can be added appropriately to improve the flotation effect of graphite. The high ion valence inorganic electrolyte solution has strong foaming effect, and it is not necessary to add a frother. The principle of inorganic electrolyte solution promoting graphite flotation is analyzed from the aspects of liquid phase property, gas–liquid interface property, contact angle and surface potential. It is proved that inorganic electrolyte solution as flotation medium can promote the effective flotation of graphite.