This dissertation presents the results of investigations concerning the influence of chosen soil physical parameters on the values of hydraulic conductivity coefficient. An optimum set of parameters of the soil solid phase was chosen, including: percent content of sand fraction, percent content of silt fraction, specific surface, determined with the method of water vapour adsorption, percent content of organic carbon, gravitational water content and water content at the potential corresponding to the field water capacity. It enabled to elaborate a physical-statistical model for direct calculation of hydraulic conductivity coefficient on the base of the knowledge of some easily measurable parameters of the soil solid phase. The proposed model makes it possible to determine the values of the soil hydraulic conductivity coefficient for 8 soil water potential values (pF 0; pF 1; pF 1.5; pF 2; pF 2.2; pF 2.5; pF 2.7; pF 3), it is from the state of full saturation to the water potential value corresponding to the point on the water retention curve, from which plant growth inhibition begins. High values of correlation coefficients and low values of standard errors of estimation, obtained for the verified soil material, both for particular soil types and for it as a whole, confirm the proper model construction (the selection of parameters of the soil solid phase as well as the use of segment regression formulas). The use of the representative experimental material (415 soil samples for the construction of the model and 145 samples for its verification), the application of uniform measuring methods and positive verification, assure that the proposed physical-mathematical model is representative and therefore especially useful.