Spin orbit torque (SOT) switching of magnetization is of intense research for developing next generation of energy-efficient spin electronic devices. Topological materials, with large Berry curvature and unusual spin momentum locking induced by band topology, are a promising platform to explore SOT phenomena at a new setting. We have observed many unusual SOT characteristics in antiferromagnetic TKM Mn3Sn and FeSn using second harmonic Hall and MOKE/ST-FMR (in collaboration with Prof. John Xiao) measurements (unpublished).