A Terahertz wave radiation source belongs to the technical field of Terahertz wave. The basic structure comprises a microwave source, a connecting wave guide and a Terahertz wave generator. The Terahertz wave generator works in a vacuum state in a tube, and mainly comprises a cathode for emitting electrons, a focusing electrode, a microwave input wave guide, a microwave cavity, an electron beam drifting and bunching pipe, an extraction electrode, a thick film capacitor, a thin film radiating antenna, an electron beam focusing magnet and a pole shoe. The invention has a simple structure, the output power and efficiency greatly exceeding that of the prior Terahertz wave generator, is suitable for large-scaled production, and has wide application prospect in the fields, such as material detection, human body imaging, component analysis, and the like.