Abstract: Low-frequency sound wave directional propagation is significantly hindered by diffraction effects, which cause rapid energy diffusion in the sound field. This remains a major challenge for miniaturizing acoustic functional devices. Based on the principle of monopole Mie resonance, this study designs a high-refractive-index subwavelength Mie structure acoustic metamaterial aimed at achieving directional transmission of low-frequency sound waves. First, based on the equivalent medium theory and multiple scattering theory, calculate the resonance frequency of Mie structural units in the monopole resonance state. Next, finite element method simulations are conducted to analyze the resonance frequency and sound pressure field distribution characteristics of the unit under plane wave excitation. Furthermore, this study explores the influence of unit structural parameters on the resonance frequency and the peak sound pressure. Finally, numerical simulations and experiments are validated that an array structure composed of four Mie units can effectively achieve the phenomenon of acoustic collimation for low-frequency sound waves. The influence of the array distribution parameters and the number of unit cells composing the array on this phenomenon is explored. The designed subwavelength monopole Mie resonance acoustic metamaterial overcomes the physical size limitations of traditional acoustic devices and has potential application prospects in low-frequency acoustic wave filters and noise suppression systems.