Since the flexible NFC tag antenna is usually in a deformed working state, in order to solve the problem of frequency offset and the performance degradation caused by the frequency offset in this working state, and to improve its applicability in the application of wireless human health monitoring, a flexible NFC tag antenna with human skin adaptation and excellent performance is designed. The antenna uses gallium indium liquid metal as a flexible conductive material, combined with PDMS flexible substrate material to enhance the stretchability and flexibility of the NFC tag antenna. Based on the principle of miniaturized NFC antenna design, this paper proposes a novel non-equal spacing structural design scheme to increase the working bandwidth of the antenna, maintain relatively stable electrical parameters, resonant frequency as well as communication distance under different deformed states and improve the working stability. The simulation and experimental results show that the working bandwidth below -10 dB of the non-equal spacing NFC tag antenna with an external size of 25 mm× 25 mm and a line spacing growth rate of 200% can reach 0. 87 MHz. Compared with an equal line spacing antenna with the same area, the maximum increase in working bandwidth is up to 52. 6%. Aiming to the particularity of the application environment of this flexible NFC tag antenna, in the stretching working state with a stretching degree of 30% and the bending working state with a curvature radius of 5 mm, the center frequency deviation of the antenna is 3. 2% and 2. 4%. The antenna communication distance is always no less than 30 mm, and it shows good working stability under deformed working states.