The present invention relates to a generation device and a generation method of terahertz waves with orbital angular momentum. The generation device comprises a first laser and a second laser; the first laser radiates a first laser beam; the second laser radiates a second laser beam; and the frequency difference between the first laser beam and the second laser beam is within a terahertz wave band. The generation device further comprises an orbital angular momentum generator, a beam combiner and a terahertz radiation generator; the first laser beam passes through the orbital angular momentum generator to generate the first laser beam with the orbital angular momentum; after the first laser beam with the orbital angular momentum and a second laser beam are combined to form a combined beam, the combined beam reaches a terahertz radiation transmitter; the terahertz radiation transmitter performs frequency mixing and filtering processing on the first laser beam A with the orbital angular momentum and the second laser beam B to generate terahertz waves with the orbital angular momentum. Through a simple beam path design, terahertz wave beams with orbital angular momentum, which are low in consumption and high in efficiency, can be obtained.