Bi2Te3 nanowires and nanoparticles are synthesized by hydrothermal method, and the nanopowders are pressed into bulk pellets by high-pressure sintering or vacuum hot-pressed. The scanning electron microscope (SEM) results and thermal properties of such bulk samples are compared. The SEM result shows that the grain size of the high-pressure sintering sample is much smaller than that of the hot-pressed sample. The thermal properties show that the electrical resistivity, Seebeck coefficient, and thermal conductivity of the high-pressure sintering sample are all better than those of the hot-pressed sample. The ZT value of the high-pressure sintering sample prepared by nanowires reaches 0.5 at room temperature, which is much higher than that of the hot-pressed sample. Therefore the high-pressure sintering provides an effective method to press nanopowders to bulk.