The invention discloses a treating method of high-hardness wastewater containing phosphorus and fluorine. The treating method comprises the steps: 1) introducing water into a reaction tank, also adding lime milk into the reaction tank, and mixing; 2) introducing the solution into a clarification tank, adding PAM (Polyacrylamide) into the clarification tank, mixing for 10min, and standing for clarification; 3) introducing a clarified liquor into a first aeration tank, leading a carbon dioxide gas into the first aeration tank, and adding Na2CO3 and PAC (Poly Aluminium Chloride) as a flocculant; 4) introducing a supernate in the first aeration tank into a filter; 5) introducing a filtered fluid into a second aeration tank, and leading the carbon dioxide gas into the second aeration tank; and 6) obtaining a solution as product water. With the adoption of the treating method, the technological process is simple, and only primary treatment and two-stage aeration are needed; the added medicaments are little in the type, and the effect is obvious; the energy is saved, the emission is reduced, CO2 is fully utilized to weaken the hardness, the stability of the water quality is good after the treatment, and the cost is low; the reaction time is short, the technological critical control points are less and are not easy to scale, and the operation is easy. The treating method is suitable for treating the high-hardness wastewater containing phosphorus and fluorine.