The invention discloses a rib cutting forming machine used for packaging semiconductor elements. The rib cutting forming machine comprises a supporting table with an inner cavity. A guiding device, afeeding device and a rib cutting device are fixedly installed at the upper portion of the supporting table, and four supporting legs are symmetrically installed at the bottom of the supporting table.The guiding device comprises an n-shaped guide rail which is fixedly installed at the upper portion of the supporting table, and a guide through groove is formed in the center of the top wall of the n-shaped guide rail. The feeding device comprises a supporting block which is installed in the guide through groove in a sliding manner. The invention further provides a use method of the rib cutting forming machine used for packaging the semiconductor elements, and the use method includes four steps. By means of the rib cutting forming machine used for packaging the semiconductor elements and theuse method of the rib cutting forming machine used for packaging the semiconductor elements, running is stable, the performance is reliable, residual ribs at the outer portion of a cylindrical shell can be cut thoroughly, damage is not likely to happen, the maintenance cost is low, the service life is long, use is facilitated, the work efficiency is greatly improved, replacing and installing of acutter are facilitated, a waste material collecting function is achieved, cleaning is facilitated, and the labor intensity of workers can be relieved.