In short-millimeter band quasi-optical network, it is a difficult problem to design and manufacture corrugated horn antennas acting as Gaussian feeds because of the accuracy of classical manufacture methods. The dimension design methods for corrugated horns were presented in term of the expected Gaussian beam parameters. The mode-matching (MM) method was carried out to numerically predict the performance of corrugated horns comprising large numbers of corrugation ridges and slots. A novel method was proposed to overcome the manufacture difficulties in short millimeter-wave band. The solution is to make the horn in a number of separate sections (either slot or ridge ring) and join them together with appropriate configuration. Two corrugated horns working respectively at 5mm and 3mm bands were realized in this technique. Finally, the performance of the two antennas was measured and the results were compared with the numerical data.