The invention discloses a terahertz detector chip. The terahertz detector chip comprises a first MOS detection tube, a second MOS detection tube, and a low-noise amplifier used for amplifying a direct current signal that is output after the signals received by the first MOS detection tube and the second MOS detection tube are rectified; the drain electrodes of the first MOS detection tube and the second MOS detection tube are jointly connected with the input end of the low-noise amplifier; the source electrodes of the first MOS detection tube and the second MOS detection tube are jointly grounded; the grid electrode of the first MOS detection tube is connected with a first patch antenna through a first impedance matching device; and the grid electrode of the second MOS detection tube is connected with a second patch antenna through a second impedance matching device. According to the terahertz detector chip, the integration of the antenna, the detection tubes and the amplifier is realized, so that the small-sized detector is achieved, the rate of finished products of the detector is improved, the cost is lowered, the double receiving and conversion of terahertz waves can be realized, the output signal can be improved in duplications, the return loss can be greatly lowered, and the transmission efficiency of signal power is improved.