Abstract: Accurate calculation of cyclic pressure dissipation is the basis of programming of bit hydraulics optimization. Based on accurate calculation of cyclic pressure dissipation with H - B fluid model, optimum hydraulic routes are designed by using operation patterns of maximum water power and maximum impulsive force, so as to select drilling hydraulics and optimum nozzle sizes. The Bingham model, power law model and H - B model are compared by using the program developed and through case calculation. Comparison shows that H - B model can give out more accurate calculation results and can fully meet the requirements of drilling engineering design.