The invention discloses a rating device for the negative pressure of vibration wire type pore water pressure gauges. The rating device for the negative pressure of the vibration wire type pore water pressure gauges comprises a multi-grade vacuum pressure generating device, a rating seal tank, a frequency measuring instrument and a computer system. The multi-grade vacuum pressure generating device is connected with the rating seal tank. A vacuum pressure gauge is installed on the rating seal tank. During rating, the vibration wire type pore water pressure gauges are arranged in the rating seal tank in an overhung manner through pore water pressure gauge cables, the pore water pressure gauge cables are connected with the frequency measuring instrument, the frequency measuring instrument is connected with the computer system, the computer system conduct fitting analysis on the frequency values measured by the frequency measuring instrument and the vacuum pressure values, measured by the vacuum pressure gauge, at the corresponding frequency, and the pore pressure rating coefficient is obtained through calculation. The invention further discloses a method for conducting rating on the negative pressure of the vibration wire type pore water pressure gauges through the rating device. By the adoption of the rating device and method for the negative pressure of the vibration wire type pore water pressure gauges, negative pressure rating can be more accurately conducted on the vibration wire type pore water pressure gauges, time and effort are saved, efficiency is high, and cost is low.