Abstract: With the rapid industrial development, air pollution and global climate change have become pressing issues. Addressing the effective removal of nitrogen oxides (NO_x), a major contributor to these problems, is crucial. Photo-oxidation technology emerges as a promising solution, offering a new, green method of NO_x removal. This technology stands out for its safety, cost-effectiveness, cleanliness, and cycle stability, making it an efficient approach to tackling NO_x emissions. In this study, we explore a novel strategy that involves the in-situ growth of ZnO nanodot arrays on surfaces of graphite-phase carbon nitride (g-C₃N₄) to construct column-supported structure composites. These composites are designed for the photo-oxidation removal of NO under visible light. By employing an ion adsorption reaction, ZnO NP/g-C₃N₄ column-supported structure composite photo-oxidizers were successfully synthesized with varying ZnO particle mass fractions of 1%, 2.5%, and 5%, respectively. The investigation revealed that introducing ZnO NP significantly increases the specific surface area of the ZnO NP/g-C₃N₄ composites compared to pure g-C₃N₄ samples, which have a specific surface area of 31.092 m²·g^‒1. Specifically, the 2.5% ZnO NP/g-C₃N₄ composites exhibited a substantial increase to 58.063 m²·g^‒1, while the 1% and 5% ZnO NP/g-C₃N₄ composites reached 37.141 m²·g^‒1 and 42.563 m²·g^‒1, respectively. This enhancement in the specific surface area, attributed to the columnar support structure, addresses the stacking issue of the g-C₃N₄ lamellae in the composites. The resulting structure is stretchier and fluffier, exposing a greater number of reactive sites. Furthermore, the construction of a heterostructure improves the energy band structure of the composites, facilitating the migration and separation of photogenerated carriers, which significantly enhances the photo-oxidation performance. During the NO photo-oxidation removal experiments, the ZnO NP/g-C₃N₄ composites demonstrated a marked improvement in photo-oxidation efficiency compared to pure g-C₃N₄. Notably, the 2.5% ZnO NP/g-C₃N₄ composites achieved a 100% photo-oxidation removal rate of NO, maintaining an effective removal performance across different NO concentrations and exhibiting robust performance in five cycles of stability tests. This study provides an effective strategy for designing and constructing high-performance photo-oxidizers and provides a technical reference for eliminating industrial NO pollutants. In addition, our study introduces a method for the photo-oxidation removal of NO and inspires new approaches in the design and synthesis of composite photocatalysts. By modulating the composition and structure of these composites, their photo-oxidation performance can be further optimized to achieve more efficient and stable pollutant removal. This advancement holds significant implications for environmental protection and sustainable development.