  We present a novel method for multi-color wavefront measurement of high-order
harmonic generation beams using the Talbot effect, validated both theoretically
and experimentally for the first time. Each harmonic maintains a unique
wavefront and produces an independent set of self-images along the optical
axis.We achieved the wavefronts reconstruction of three harmonics in a single
measurement scan, expanding the spectrally-resolved capability of the
conventional Talbot effect wavefront sensor. This breakthrough introduces a
novel tool for studying the multi-color wavefront in high-order harmonic
generation, unlocking the potential to investigate spatiotemporal ultrafast
nonlinear dynamics in attosecond pulse formation on a shot-by-shot basis.
