Abstract: Crop phosphorus uptake is influenced by the rate of soil P supply. Soil P supply to crop depends on root system morphology: root length. root surface area, root density and so on, meanwhile also depends on kinetics of root absorption phosPhorus- Rate of soil supply P can be changed when adding P fiertilizer in soil, so that it caused crop root System morphology and P uptake change. This program from three parts studied effect of P placed on root system morphology and P uptake: (1) Effect of different P rates placed in soil on cotton root system morphology and P uptuke. (2) Effect of one P rate placed in different soil volumes on cotton root system morphology and P uptake. (3) Effect of different P rates placed in different soil volumes on cotton root system morphology and P uptake. The research has shown that length. surface area of cotton root and P uptake by root area increased when P placed in soil. so make cotton growth greater. When P fertilizer placed in part volumes soil, P stimulated cotton root growth that grew in soil of P-treatment. this can be described by the relation. Y-X0.72 where Y is the proportion of roots in soil of P placed, X is the fractional volume