Abstract: In this paper, the effective radius of oil well is included in the insideboundary in the problem of flow of fluid in a reservoir, thus a new model has been built. Taking the wellbore storage and skin into consideration, an exact solution of the pressure distribtion in a homogeneous reservoir. In the case of an infinite outer boundary, a finite closed boundary and finite boundary with the constant pressure. Furthermore, this paper has described dimeusionless bottom draw-down and pressure derivative curves for both infinte and closed boundary reservoirs under constant well yield. These are equivalent to the type curves used in modern well-testing analysis generally. These type curves are more exact than those derived by Gringarten et al.