Nutrient adsorption characteristics of soil are important issues in the study of soil chemistry and plant nutrition. An experiment was carried out on NH₄⁺, PO₄^3- and K⁺ adsorption in 9 soils. Results show that Langmuir, Freundlish and Temkin isothermal adsorption equations described the sorptions quite well, but they were not perfect. A concept of “shape factor d ” of genecology was introduced to create a new adsorption model based on the Langmuir equation. Theoretical analysis indicates that the new adsorption model reflected comprehensively dynamic characteristics of the three isothermal adsorption equations. Simulation results show that the soils which the three isothermal adsorption equations didn’t fit well, were well described by the new model. The new model was higher in simulation precision （R²） and lower in standard deviation than the three isothermal adsorption equations. Its shape factor “d ” varied between 0.608 0~2.929 0, demonstrating effect of physical-chemical properties of the soils on shapes of NH₄⁺, PO₄^3- and K⁺isothermal adsorption curves. The linear correlation coefficient between the new model and Langmuir equation inq_m values of NH₄⁺ and PO₄^3- and K⁺ was 0.851 5^**, 0.825 8^** and 0.912 8^** (n=9) respectively. According to the new adsorption model, soil physicalchemical analysis show significantly positive linear correlation between q_m values of PO₄^3- or K⁺ calculated by the new model and soil organic matter content, between q_m values of NH₄⁺ or K⁺ and CEC, and between q_m value of NH₄⁺ and soil available nitrogen as well, but significantly negative correlation between q_mvalue of PO₄^3- and available phosphorus in the soil. The new adsorption model, concise in mathematical form, provides a new approach to using a uniform model for quantification of NH₄⁺, PO₄^3- and K⁺ adsorption characteristics in soil.