To address the problem that the performance of UHF RFID tags in the dense environment of vaccine transportation is affected by the mutual coupling effect and liquid environment, the computational expressions of mutual impedance and power transmission coefficient of tags under the action of proximity liquid interference and tag mutual coupling effect are derived from the perspective of impedance change of single tags in liquid environment based on inductive coupling model and using two-port network analysis method. Using the control variable method to design simulation experiments and actual measurements, the simulation measurement results show that under the interaction of multiple environments, the liquid environment mainly affects the real part of the label, and the mutual coupling effect of the label mainly affects the imaginary part of the label impedance; the research results have certain guiding significance for the label design and the application of the label in the cold chain transportation of vaccines.