This paper reports the numerical simulation of turbulent flow field in rockbits with the k-ε turbulence model and a new twenty-one point scheme for pressure correction equation, which greatly improves the synchronous convergence ane the dependence ofcoupling between velocity and pressure on the pressure relaxation factor. It is numericallyverified that adaptive-manually technique is effective to generate more continuous, smoothand orthogonal Laplace grid system. Numerical results show that there exist vortices andlower pressure domains around the damaged zone, which strengthen the wear by solidparticle in the drilling nuid and induce the cavitation effect, finally causing the erosion anddecrease in the life of rock bit. The damage could be avoided by some modification of theinternal flow structure of rock bit. This paper reports the numerical simulation of turbulent flow field in rockbits with the k-ε turbulence model and a new twenty-one point scheme for pressure correction equation, which greatly improves the synchronous convergence ane the dependence of coupling between velocity and pressure on the pressure relaxation factor. It is numericallyverified that adaptive-manually technique is effective to generate more continuous, smoothand orthogonal Laplace grid system. Numerical results show that there exist vortices andlower pressure domains around the damaged zone, which strengthen the wear by solidparticle in the drilling nuid and induce the cavitation effect, finally causing the erosion anddecrease in the life of rock bit. The damage could be avoided by some modification of the internal flow structure of rock bit.