Abstract: Drag coefficients and shielding effects of steel tubular members are important parameters for accurately calculating wind loads acting on tubular steel transmission towers. Wind tunnel tests on nine full scale models and scaled models of tubular members under seven flow velocities were carried out. The wind forces or pressures acting on tubular member models were measured. The effect rules on drag coefficients of tubular members were analyzed, which can be induced by Reynolds number, turbulent intensity and the included angle between the front face of tower segments and the vertical plane. Effects of blockage ratio of the wind tunnel on drag coefficients of tubular members were also analyzed. Modification factors and the fitting curve for the included angle effects were proposed. Drag coefficients for steel tubular members in transmission towers were suggested for design purpose. The distance ratio of steel members used in transmission towers is from 7 to70. Based on the wind tunnel tests, effects of the distance ratio on the shielding effects of leeward steel tubular members in subcritical regions were determined. The relationship curve between the distance ratio and the shielding factor was proposed for steel tubular members. In subcritical regions, the experimental shielding factors for different tubular size under the same distance ratio are close to each other. The results can provide reference and basis for refine calculation of the wind loads acting on steel tubular transmission towers.