A laboratory experiment was conducted to study the release of phosphorous. the study included taking three different samples in their content of gypsum (243,138.67) g kg^-1 observations, symbolized by (G1, G2, and G3) and different in their physical and chemical properties, ... Bacillus cereus ,Pseudomonas putida to find out the efficiency of bacteria in releasing phosphorous, the amount of phosphorous released at the functional periods of 2, 4, 8, 24 hours and 2, 4, 7, 14, 21 days was calculated and the amount of phosphorous for each time and in order to obtain the best equation to describe the kinetics of phosphorus liberation in different in its content From gypsum, kinematics equations were used (zero order equation, first order equation, diffusion, forces function, elovig)The results showed that the amount of liberated phosphorous decreases with the increase in the amount of gypsum and increases with the increase in the incubation period. The lowest amount of liberated phosphorous in the G3 sample at the time of 2 hours was 1.7 mg p L^-1 for the uninoculated treatment. The highest amount of liberated phosphorus was in the G1 sample at the time of 21 days. It was 6.9 mg p L^-1 for the treatment inoculated with P putida it had the advantage in increasing the liberated amount of phosphorous, and the best kinetic equation described phosphorous liberation for each soil of the study was the equation of the force function, and the values ​​of the coefficient of liberation speed for sample G1 amounted to (0.025, 0.89, 0.089) mg kg day^-1 and for sample G2 it amounted to (0.025, 0.094, 0.078) mg kg day-^1, while the sample G3 was (0.044, 0.134, 0.139) mg kg day^-1 for unvaccinated treatments, B. cereus and P. putida respectively