Abstract: Inorder to study the influence of the balancing hole meridional angle of the high speed centrifugal pump on its internal and external characteristics and the axial force of the rotor, taken a high speed centrifugal pump with a rotational speed of 30 000 r/min as the research object, the whole flow field was numerically calculated by using the N-S equation and the RNG k-ε turbulence model. The results show that with the increase of the meridional angle, the shaft power of the high speed centrifugal pump decreases to 2.8% of maximum shaft power, and the efficiency increases to 1.1% of the minimum efficiency, and the maximum variation of head is 1.5% of the designed head and appears the extreme point. With the increase of the meridional angle, high pressure jet leaked by balancing hole squeezes the main stream of centrifugal wheel inlet smalle. When the meridional angle is within the range of − 30° ≤ θ ≤ − 10° and 0° ≤ θ ≤ 20°,with the increase of the meridional angle, rotor axial force of the high speed centrifugal pump decreases. When the meridional angle is θ=0, the axial force of the rotor increases sharply and reaches the maximum point. Comparing with the traditional installation method of balanceing hole those meridional angle is θ = 0°, the axial force decreases by 67.92% and can be effectively balanced when the meridional angle is θ = 20° in this study.