The invention discloses a three-dimensional optical parameter oscillation terahertz wave radiation source. The three-dimensional optical parameter oscillation terahertz wave radiation source comprisesa pumping source, a MgO:LiNbO3 crystal, a pumping light recover and a reflecting mirror, wherein the reflecting mirror is arranged around the MgO:LiNbO3 crystal, a plane where first pumping light andtenth pumping light are propagated is a plane determined by an X axis and a Y axis, a Z axis is perpendicular to the plane where the first pumping light and the tenth pumping light are propagated, apropagation direction of the pumping light emitted from the pumping source is an X-axis negative direction, and a propagation direction of a terahertz wave is a Y-axis positive direction. The three-dimensional optical parameter oscillation terahertz wave radiation source provided by the invention has the following advantages that the pumping light is circularly used, multiple beams of terahertz waves can be generated, and the terahertz wave energy is effectively improved; by changing an included angle between the pumping light and Stokes light, a terahertz wave with a tuning frequency can be obtained; a tuning mode is simple and is flexible to operate; the terahertz wave is emitted perpendicular to the MgO:LiNbO3 crystal, any coupling output device is not needed, and the output loss of theterahertz wave is effectively reduced.