In this work we compare the performance of the semiempirical PM6 method with a more accurate DFT method when applied to Ru-catalyzed olefin metathesis. We demonstrate that the PM6 method reproduces with interesting accuracy the geometries located with a DFT approach. As for the energetics, the relative DFT stability of the metallacycle with respect to the coordination intermediate is reproduced with reasonable accuracy by the PM6 method, whereas the olefin coordination energy and the energy barrier of the metathesis step are overestimated. Further, for the same system we performed a PM6-based meta-dynamics study of the olefin metathesis reaction, which indicated a reasonable good behavior of the system also under dynamic conditions. In conclusion, the obtained results validate the use of the semiempirical PM6 method for preliminary and computationally fast screening on new ligands/substrates in Ru catalyzed olefin metathesis.