The analytic method and computational fluid dynamics (CFD) simulations are employed in calculating and comparative analysis on flow of the fan based on fancooled high speed motorized spindle. The influence of blade number and blade type on cooling air volume and total pressure was studied, and an improvement design scheme was proposed. The results show that the cooling air volume confirmed by the CFD simulations agrees with the one obtained by analytic method. The fan has good performance in 9 blades. The radial blade can provide higher total pressure, but its cooling air volume may not be larger. The cooling air volume is related to the static pressure in the total pressure, and the larger the static pressure value, the larger is the cooling air volume. The improved fan is better in performance compared to the prototype, and the air volume is increased by 23.6%.