Non-Hermitian acoustic systems featuring balanced gain and loss have gained significant popularity owing to their potential applications in multifunctional devices. In this paper, we introduce the concept of parity-time ($\mathcal{PT}$) symmetry to zero index metamaterials (ZIMs) to investigate the transport of sound waves through a $\mathcal{PT}$-ZIM junction in a waveguide system. The $\mathcal{PT}$-ZIM junction is initially established by doping two acoustic cylinders with identical geometry and conjugate refractive indices into the ZIM, with one being gain and the other loss. It is found that the balanced gain and loss induce a perfect resonance transmission (PRT) against a backdrop of perfect reflection, with the resonant linewidth being controllable and determined by the gain/loss factor. Furthermore, we demonstrate the pseudo-$\mathcal{PT}$-symmetry and present a more comprehensive PRT in scenarios where the cylinder geometries are nonidentical, and feature distinct gain and loss factors. The fundamental principle remains a delicate equilibrium between gain and loss, however, the sound localization effect in the cylinders is significantly enhanced due to the differentiation in radii. This work offers a pathway for exploring non-Hermitian acoustics in ZIM, holding promising applications in sensing and nonlinear acoustics.

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• Acoustic metamaterials
• Acoustics
• Non-Hermitian systems
• PT-symmetry