Disclosed are a corrosion-resistant gas delivery assembly and a plasma processing apparatus. An inlet gas delivery component and a gas diffusion component are combined correspondingly with an inlet gas accommodation hole and a diffusion accommodation space that are arranged in a liner body, to form a multi-component structural configuration, which avoids direct contact of the process gas with the liner body due to liner body surface defects caused by high temperature. The advantages as offered include: effectively preventing the process gas from corroding a gas delivery assembly and the plasma processing apparatus, and solving the problems such as metal contamination and solid particle contamination in the reaction chamber caused by the corrosive fraction in the process gas; besides, the multi-component structural configuration facilitates routine maintenance.