It was studied that the effect of different kinds of organic acids and their concentrations on the soil phosphate absorbing capacities by way of isothermal absorption in the brown soil. It concluded that the larger the number of functional group (-COOH, -OH) of organic acids was, the greater the effect on decreasing soil phosphate absorbing capacities, and the affected order was as follows: Lemon acid>oralic acid>tarlaric acid>benzolic acid>acetic acid. Secondly, as concentrations of organic acids increased, the soil phosphate absorbing capacities decreased at the same pH value. And Thirdly, the effect of solutions of organic acids or phosphate added to the soil with different orders on the phosphate absorbing capacities was also different. The decreased order was as the following: the first was by adding phosphate solution before organic acids, the second was by adding phosphate solution after abandoning centrifugal soil organic acids solution, and the third was by putting into phosphate solution after the organic acids absorbed.