As a fundamental production factor of economic development, rational land allocation is relevant to economic development and a significant factor affecting urban air pollution. This study analyzes 284 cities in China to investigate the impact of land resource misallocation on air pollution and the underlying mechanisms. The relevant findings are fourfold. First, land resource misallocation increases urban air pollution. Second, land resource misallocation inhibits technological innovation, government technology investment, and foreign direct investment, increasing local air pollution. Third, the impact of land resource misallocation on air pollution is affected by heterogeneous conditions, including geographic region, city type, and city size. Finally, based on the air pollution caused by land resource misallocation, local governments should optimize the land supply structure and improve technological innovation and environmental investment.