In this work, we describe experimental water vapor forming of hollow filter rods. The morphology, microstructure and mechanical property of hollow filter rods were carefully investigated. The forming mechanism of hollow filter rods was also discussed. The results demonstrated that a well-formed product was successfully obtained under the best process parameters. The circumference means of tested samples can be mainly determined by water vapor pressure and plasticizer concentration. However, the roundness of hollow filter rods depended on cellulose tow content. The occurrence of surface fuzzing and bending deflection was largely as the result of incomplete curing effect while the emergence of intermittent formation may rely on the tow feed volume during the forming process. The acceptable hardness of hollow filter rods was up to 92.27 % in the experiments. An improvement in hardness was mainly attributive to crisscrossing three-dimensional structures formed inside the filter rod. A model consisting of the diffusion stage, crosslinking stage and solidifying stage was proposed to illustrate the formation of filter rods.