Abstract: The spatial function division of urban agglomeration is an advanced form of regional division of labor, and exploring its impact mechanism on haze pollution is of great significance for promoting the sustainable and healthy development of urban agglomerations. On the basis of expounding the mechanism of the spatial function division of urban agglomeration affecting haze pollution, an empirical analysis based on panel data of the Yangtze River Delta urban agglomeration. The study found that the enhancement of urban function specialization caused by the spatial function division of urban agglomeration has a significant inhibitory effect on regional haze pollution. Improving the degree of specialization of urban functions will not only help to reduce the level of haze pollution in the region, but also inhibit the haze pollution in adjacent areas. The haze reduction effects of the spatial function division of urban agglomeration is established in the test of central city group, the non-central city group and the non-G60 science and innovation corridor city group; Compared with the central city, the functional specialization of the non-central city group is improved, which has a greater inhibitory effect on haze pollution. The spatial function division of urban agglomeration mainly reduces regional haze pollution through the effect of industrial structure upgrading and labor endowment effect. Finally, the policy enlightenment is expounded from the aspects of constructing the development pattern of complementary functions.