The crater retention, texture, microaggregate composition and other physical properties of main soils in north Anhui Province were measured. It has been tounde that the function θ=AS^-B could well simulate the soil water-retention curves under condition of medium and low suction, from this the specific water capacities of these soils were derived; and then the specific water capacities were obtained by analytical solution:C_θ=-(dθ/ds)=ABS^-(B+1).It is suggested that A·B value might be used to evaluate soil waterretention ability. Function type Ⅰ of S-shape curve (P=1/a₂+b₂c^-lgD) has been used to fit the particle distribution curve and type ⅡN(μ,σ)=a₂+b₂ lgD to lit the microaggregate distribution curve. The results obtained were satisfactory. Parameters of these functions and their relationship to soil water condition and otherr physical properties are also discussed.