Terahertz (THz) refers to an electromagnetic wave with a frequency of 0.1~10 THz and a wavelength of 30~3 000 μm. Because the frequencies of vibration and rotation of many small molecules in nature are in the terahertz band, and the low electron energy characteristics of terahertz will not cause damage to the samples to be tested in the experimental process, terahertz technology is widely used in the fields of nondestructive testing, biomedicine and so on. However, there are few reports on terahertz in the field of ferromagnetism. Therefore, in this study, terahertz transmission characteristics of new magnetic material, carrier liquid, a magnetic fluid component, are studied by terahertz time domain spectroscopy. Magnetic fluid is a new functional material with both liquid fluidity and solid magnetism, breaking traditional magnetic materials' solid form. The magnetic fluid is composed of Fe₃O₄ nanoparticles and a carrier liquid. In the previous research results, it is found that magnetic fluid not only has a good magneto-optical effect but also has high transmittance to terahertz at a certain frequency. In addition, under the action of an extremely low-frequency electromagnetic field, it can be used in medical tumor therapy and as a drug delivery system for targeted therapy. Due to the high cost of carrier liquid, a magnetic fluid component, microfluidic technology is used in this experiment. Microfluidic technology has the advantages of less consumption of detection samples, fast detection speed, and can design channels according to experimental needs. Therefore, it is a convenient and flexible detection method. In this study, a sandwich terahertz microfluidic chip was made of quartz material with high transmittance to terahertz waves. First, put two pieces 3 cm×3 cm×2 mm quartz glass is used as the substrate and cover, and then the strong adhesive double-sided adhesive tape is cut and engraved into a hollow pattern to form 2 cm×2 cm square area, and then bond the cover sheet and the substrate through the engraved strong adhesive double-sided tape, with a channel thickness of 50 μm. It can be used to detect a small amount of liquid, and the carrier liquid can be made into a thin film. Then, combining terahertz technology and microfluidic technology, the terahertz transmission characteristics of carrier liquid are studied by terahertz time-domain spectroscopy (THz-TDS). The study of terahertz time domain spectroscopy and frequency domain spectroscopy shows that the signal intensity of microfluidic chip with carrier liquid is higher than that of empty microfluidic chip. This discovery provides technical support for the in-depth application and research of carrier liquid.