The term “polarization-dependent Talbot effect” means that the Talbot self-imaging intensity of a high-density grating is different for TE and TM polarization modes. Numerical simulations with the finite-difference time-domain method show that the polarization dependence of the Talbot images is obvious for gratings with period d between $2\lambda$ and $3\lambda$ . Such a polarization-dependent difference for TE and TM polarization of a high-density grating of $630\mathrm{lines}∕\mathrm{mm}$ (corresponding to $d∕\lambda =2.5$ ) is verified through experiments with the scanning near-field optical microscopy technique, in which a $\mathrm{He}–\mathrm{Ne}$ laser is used as its polarization is changed from the TE mode to the TM mode. The polarization-dependent Talbot effect should help us to understand more clearly the diffraction behavior of a high-density grating in nano-optics and contribute to wide application of the Talbot effect.