Numerical analysis and simulation of cavitating flows due to appearance and its application in the maritime industry, water turbomachinery, hydrofoils, underwater vehicles, etc. have specific importance. For this reason in this research, the effect of blowing on hydrodynamic behavior of cavitating flows over hydrofoils has been investigated. Jameson's finite volume method and power-law preconditioning method with single-phase cavitation model (Barotropic model) have been used to the analyzing of cavitating flow. The stabilization of solution has been achieved with help of the second and fourth-order dissipation term. Explicit four step Runge-Kutta method has been used to achieve the steady state condition. As regards the cavitation often occurs at high Reynolds number, to facilitate the simulation the inviscid flow equations are considered. For apply the blowing from hydrofoil surface, a jet has been placed on hydrofoil’s upper surface. The parameters of jet location, blowing velocity ratio, blowing angle and width of jet are investigated and simulation has been performed for two different cavitation numbers. The numerical results show that the power-law precondition increases the convergence speed significantly. Blowing reduces the cavity length, lift and pressure drag coefficients compared to no blowing case. Also the increase of blowing velocity ratio, blowing angle and width of jet, decrease the cavity length, lift and pressure drag coefficients.