The subharmonic heterodyne combined with cut-off waveguide method is proposed to measure the frequency of 0.14 THz high-power nanosecond pulse in this paper. Using the cut-off waveguide method, the frequency range of the terahertz pulse is determined, in which two non-standard rectangular waveguides with cut-off frequencies of 0.125 and 0.15 THz are separately used as a receiver. According to the preliminary result, the subharmonic order is chosen to be 8, while the frequency of local oscillator is set to be in a range of 15—20 GHz. A series of tests on the 8th harmonic mixer is done using the pulses in Ka-band and the 0.14 THz continuous wave source, separately. Experimental results indicate that the mixer can be used in the heterodyne measurement of 0.14 THz nanosecond pulse. Finally, the heterodyne measurement is carried out on the high-power terahertz puls source, and an accurate frequency of 0.1465 THz is determined in this experiment. This novel method, which greatly reduces the frequency requirement of the local oscillator, is proved to have a good performance in the frequency measurement of 0.14 THz nanosecond pulse, and probably provides a new idea for frequency measurement of pulses in the long-wavelength terahertz-band.