This paper simply discussed upon speed regulating by frequency converting used in design and manufacture of high-power and high-speed frequency conversion mixer, and the new control technology about the speed regulation of motor by changing the frequency and the amplitude of voltage. Designs are introduced on high-power digital frequency-converting speed regulator by using the single chip computer 89C51 as the control core, taking SPWM controlling chip special for the SA866 and PS21255 IPM power module as the mainly controlling module and high-speed conversion motor with small volume and high-power. The settlement to multistage harmonic suppressing for speed regulating by frequency conversion, and heat dispersion and noise suppressing for high-speed and small-volume conversion motor are also presented.