In this study, we observed a misfit (MS) dislocation in a SiGe film on a Si substrate (SiGe/Si) by laser scattering, which is a nondestructive method; furthermore, using this technique, we determined the velocity of a threading (TH) dislocation in a 56-nm-thick Si0.76Ge0.24 film over a wide temperature range. It was found that the TH dislocation velocity is described by an Arrhenius plot with an activation energy of 1.9 eV. The TH dislocation velocity at 375 °C is observed on the extrapolation of the Arrhenius plots obtained in the high-temperature region; this indicates that the TH dislocation motion in a Si0.76Ge0.24 film is thermally activated at this low temperature. It was also clarified that this technique is effective for regions with a high density of MS dislocations.