[en] It is important that Magneto-hydro-dynamic (MHD) flow velocity distribution in cross section of duct are related to materials compatibility, heat transfer and MHD pressure drop. The experimental results of velocity distribution across rectangular duct on the center plane, and of two-dimensional (2D) MHD pressure drop effect due to 2D velocity distribution are presented. The results showed that the boundaries and core velocity distribution on the center plane of the duct are increasing with Hartmann number M increasing, but the approach theory expected that core velocity distribution is decreasing with M increasing. The 2D effect factor for MHD pressure drop from the 2D velocity distribution was also carried out. This explained the reason why numerical results of MHD pressure drop gradient are lower than that of experiments