The photon energy of THz wave is only meV, which is much lower than the bond energy of various chemical bonds, so it will not cause harmful ionization reaction to biological tissues; on the other hand, because the characteristic energy of rotation and vibration of most biomolecules is in the THz range, THz wave can be used to identify the biomolecules. Water is the most important liquid in a biological medium, the interaction between biomolecules and liquid water determines its biological activity, so it is very important to study the terahertz characteristics of liquid water. As a polar liquid, the dipole-dipole interaction and the hydrogen bond between polar molecules in the liquid will have a great absorption effect on the THz wave, making it very difficult to study the characteristics of biomolecular dynamics in a liquid environment by using THz technology. Microfluidic technology controls the thickness of the liquid sample by changing the depth of the liquid channel in the microfluidic chip reduce the interaction distance between THz wave and liquid sample, thus greatly reducing the absorption of THz wave by water. In this study, a reusable sandwich microfluidic chip was fabricated using double-sided adhesive and Zeonor 1420R material with a THz transmittance of 95%. The liquid channel’s length, width and depth are 2 cm, 5 mm and 50 μm, respectively. In addition, a refrigeration system is designed and manufactured, which is composed of a refrigeration chip, heat dissipation module, temperature sensor, incubator and temperature controller. The refrigeration system can cool the internal environment of the incubator and keep a constant temperature to a certain extent. During the experiment, the microfluidic chip filled with water is placed in the incubator, and the refrigeration system cools the water in the microfluidic chip. The THz transmission is measured every 1 ℃ from 8 to -3 ℃. Through the analysis of the experimental data, it is found that the THz transmission of water increases with the decrease of temperature, it shows that the absorption of THz wave by water decreases with the decrease of temperature. The results lay a foundation for the future study of THz absorption characteristics of liquid samples by microfluidic technology in different low-temperature environments and provide technical support for the application and development of THz in the biological field.