In light of the drawbacks of the 2-D wing, with the reference of traditional adjustments on the blower, a new hydraulic design method for the inlet guide vane was proposed. It was supposed that the fluid at the outlet of the inlet guide vane satisfied the conditions at the moment of uniform velocity. The spatial shape of the blade was controlled by the distributed rule of the blades, which were at staggered angles along the meridional streamline; this could be determined with a quarternary polynomial. A point-by-point integration method was adopted to draw the bone line of the blade. The blade was thickened on two sides on an unwrapped cylinder surface. Once complete, the spatial guide vane was used for a centrifugal pump, and the experiment was performed with the inlet guide vane fixed at various axial positions and pre-whirl angles. The results indicated that the designed guide vane enlarged the high efficiency scope and improved the hydraulic performance of the centrifugal pump. When compared with the performance of the centrifugal pump without inlet guide vane, the peak value of efficiency was enhanced by 2.0% after the 3-D guide vane was installed. This method improved efficiency and saved energy for the centrifugal pump.