Abstract: The block water characteristics and backwater height of skew bridges are experimentally studied with the sketch model of the Hegong bridge of a speedway. By comparing and analyzing the measured water level, threedimensional velocity distribution and turbulent character around the bridge location, the calculation method for the backwater of skew bridges is improved and the reduction factor of block water width is presented. Verification results show that the corrected velocity and backwater height agree well with the measured values in the sketch model test.