Abstract: A miniaturized interdigital H-shaped spoof surface plasmon polaritons (SSPP) transmission line structure is proposed to reliably realize high-frequency signal transmission in a highly integrated communication system. Coplanar double conductor structure is designed, and the interdigital structures are designed at metal rectangular groove to achieve the regulation of dispersion characteristics and size reduction. Meanwhile the equivalent circuit model is deduced to verify the miniaturization design principle, and the performance of transmission line under mechanical deformation is analyzed. The simulated and measured results indicate that compared with conventional SSPP, the interdigital H-shaped SSPP transmission line can obtains the same bandwidth from 3 GHz to 15.25 GHz, while it features a line-width reduction up to 79.5% and the size is only 2.28λ_g×0.098λ_g (λ_g is the wavelength of the center frequency). The bandwidth of the fabricated line remains about 3−12.90 GHz under flat and deformed states. The measured results are in good agreement with the simulation results. The structure is characterized by high frequency, miniaturization and ultra-thin flexibility, which has potential application prospects in ultra small and high-speed communication system.