The invention discloses a system and a method for generating high-strength broadband terahertz wave by means of liquid column. The system comprises a laser, a spectroscope, a chopper, a first off-axisparabolic mirror and the liquid column, wherein the laser, the spectroscope, the chopper, the first off-axis parabolic mirror and the liquid column are successively arranged in an optical path; the foal length of the first off-axis parabolic mirror is one inch; the direction of the liquid column is vertically downwards; the laser is used for transmitting a horizontally polarized laser beam; the horizontally polarized laser beam is divided into a pump light beam and a detecting light beam through the spectroscope; the pump light is modulated by the chopper and then is focused to the liquid column by the first off-axis parabolic mirror; and a terahertz wave radiation source which can radiate the high-strength broadband terahertz wave is formed at the liquid column. According to the system and the method, the liquid column is utilized for generating the terahertz wave, and high generation efficiency is realized. The system and the method have advantages of simple system structure, low construction cost, easy maintenance and high reliability. The system and the method fill in gaps in the field of current high-strength broadband terahertz wave generation technology and have relativelyhigh scientific research value and relatively high application value.