A high-sensitivity terahertz microfluidic sensor based on the irregular U-type structure is proposed. The influence of the length, width, and angle of the metal wires in the sensor’s metal structure on the quality factor (Q factor) and the absorptivity of the sensor and that of the microfluidic channel height and the cap thickness on the sensing properties of the sensor are studied with simulation software. Finally, the detection performance of the sensor in glucose solutions at different mass fraction is calculated by simulation. The results show that the best combination of structural parameters for the sensor is L₁=84 μm, L₂=82 μm, L₃=52 μm, W=5 μm, and θ=60°, in which case the Q factor of the sensor can reach 24 and the sensitivity can reach 313 GHz/RIU. In short, this kind of microfluidic sensor with a high Q factor and high sensitivity has great application value in the field of label-free trace detection.