In general, a colloidal method employing polyvinylpyrrolidone (PVP) as the stabilizer has been proven particularly suitable for preparing Pd nanoparticles (Pd-NPs) with controlled morphology and size. However, this surfactant will seriously cover the Pd-NP surface, which is detrimental for catalytic activity. In this paper, we reported a method to remove PVP from the carbon nanotube (CNT) supported Pd nanocubes (Pd-NCs) and Pd nanooctahedra (Pd-NOs) by steam treatment in a lab-made reactor. We found that this method can not only efficiently remove PVP from the Pd-NP surface, but also can well maintain the original structure of Pd-NCs and Pd-NOs, dramatically enhancing the catalytic performance. The present approach may promote potential applications of Pd-NPs prepared by colloidal methods in catalytic fields.