The study was conducted to investigate the adsorption process of phosphorus (P) and to determine P supplying parameter. The study consisted taking three soils samples differed in gypsum content G1, G2, and G3 (46, 148, and 244 g.kg-1), respectively, and differed in their physicochemical characteristics. P adsorption reactions was studied at three conditions, the first was the original state, the second after removal of gypsum and the third after removal of gypsum and carbonates. Five concentrations of P were added (2.5, 5, 10, 20, and 40 mg.kg-1) and three adsorption equations were tested (Langmuir single surface, Langmuir double surface, and Freundlich) to indicate their validity. The results were as follows: Adsorption study showed the superiority of Langmuir with single surface equation over Freundlich equation. Adsorption study showed that the quantity of P adsorbed increased with the increase in added P. Adsorption study showed also that the three soils possess a high adsorption capacity for P the average values for each soil reached (583, 177.7, and 189.8) and low binding energy for P the average values for each soil reached (0.075, 0.127, and 0.083) for the soils G1, G2, and G3 respectively. The study showed that the highest values of supplying parameter were for the soil G2 after gypsum removal (1.38) and for the soil G3 after gypsum removal (1.59) and after gypsum + carbonate removal (1.5).