The invention discloses a device and method for measuring the model flow-induced noise in a working section of a water tunnel, and belongs to the field of optical measurement. The device comprises a gravity-type low-noise water tunnel 1 and a measurement device. The device is characterized in that the gravity-type low-noise water tunnel 1 consists of an upper water tank 10, a straight vertical tube 11, a shrinkage section 12, a working section 13, a diffusion section 14, a water drain pipe 15, and a reverberation box 16; the bottom of the upper water tank 10 is connected with the straight vertical tube 11, and the tail end of the straight vertical tube 11 is sequentially connected with the shrinkage section 12, the working section 13, the diffusion section 14 and the water drain pipe 15; the reverberation box 16 is added to the working section 13; the measurement device comprises a support 2, a damping pad 3, a circular cake-shaped air bag 4, a pulsating pressure sensor 5, a hydrophone6, a signal source 7, a power amplifier 8 and a spherical sound source 9; the signal source 7 emits a single-frequency sine signal, and the single-frequency sine signal passes through the power amplifier 8 to reach the spherical sound source 9; the pulsating pressure sensor 5 and the hydrophone 6 receive the sound signals emitted by the spherical sound source 9.