The invention discloses a light control terahertz modulator.The light control terahertz modulator comprises a dielectric substrate, side edge metal tapes, a metal filtering structure and a light dependent resistor array, wherein the metal filtering structure and the light dependent resistor array are both located on the surface of the dielectric substrate, the light dependent resistor array is composed of a plurality of parallel light dependent resistor tapes, each light dependent resistor tape is composed of a plurality of light dependent resistors arranged at equal intervals, the horizontally adjacent light dependent resistors are connected in series through horizontal metal wires, and the metal filtering structure is composed of a plurality of parallel metal tapes; the two side edge metal tapes are located at the two sides of the metal tapes and light dependent resistor tapes respectively, and the metal tapes and the light dependent resistor tapes are arranged in parallel alternately.The terahertz wave regulation effect of the terahertz filtering structure and the light control property of the light dependent resistors are fully combined, an electrode structure is not needed, the system modulation speed is not limited by RC constant, modulation speed is higher than 10 ns, and relative modulation depth is larger than 80%.