In order to solve the problem of unstable interface in the conventional Czochralskysingle crystal growth interface, on the basis of the conventional automatic control theory of the single crystal equal diameter, through raw material supplement device, the crystal raw materials equal to the crystal grow amount being added constantly into the crucible to stable the height of crystal growth liquid surface. Then, the real-time diameter change of the crystal is measured by the optical amplifier and charge coupled device (CCD) imaging device, and the crystal rotation speed is adjusted by this rate of change, and finally the crystal growth interface is always maintained in a relatively stable ideal state to ensure that the crystal shape conforms to the setting requirements and the internal quality in the crucible stable crystal growth on the surface of the liquid height is not changed, and then through the optical amplifier and CCD imaging device measuring crystal diameter variation in real time, in order to adjust the crystal rotation rate, eventually make crystal growth interface is always maintained in a relatively stable state of ideal, ensure crystal conform to the requirements of the set and the internal quality of excellent shape.