The invention discloses a high-power terahertz radiation pulse source which is efficiently generated by the multiplexing of pump light. The high-power terahertz radiation pulse source which is efficiently generated by the multiplexing of pump light comprises a photonic crystal fiber femtosecond laser amplifier, a beam pulse wave surface tiltometer and a dual-purpose dispersion compensator, a multiplexing cavity length matching control system, a pump light multiplexing cavity, a multiplexing cavity length adjustor and a terahertz radiation pulse emitter. The invention has the advantages that the photonic crystal fiber femtosecond laser amplifier is adopted; by using a multipass cavity structure and a grating for dispersion compensation and a beam pulse wave surface tilt method, the pump light utilization rate is improved; the theory limit that the efficiency of the pump light converted into THz radiation is extremely low is overcome, and the high-power running is realized; in addition,the invention has simple whole structure, good stability and low running cost.