Atmospheric turbulence and telescope aberrations all contribute to image degradation with ground-based telescopes. For measuring the telescope aberration with the disturbance of turbulence, a method based on phase diversity has been developed. Many instantaneous wavefront are independently reconstructed from pairs of simultaneously recorded focused and defocused short-exposure images using phase-diversity method. After that, by averaging these reconstructed wavefronts, the telescope aberrations are separated from dynamic wavefront induced by turbulence. The computer simulation of estimation of telescope aberration using phase-diversity method is conducted. The simulation shows phase-diversity method can estimate the telescope aberrations effectively and root-mean-square error is about 0.08 wavelengths.