As one of the most important production factors, land allocation profoundly affects economic activities and industrial development. Local governments in China monopolize the primary land market and widely adopt an industrial-favoring land allocation strategy. The favoritism towards industries may exacerbate regional environmental pressures. Using the two-way fixed effect model and spatial Durbin model combined with data from 278 cities in China from 2006 to 2018, this study empirically examines the impact of industrial-favoring land allocation strategy on urban carbon emissions. And we contribute theoretically and empirically to the transmission mechanism. The results show that: first, the industrial-favoring land allocation strategy significantly exacerbates urban carbon emissions. A 1 unit increase in ILAS leads to a corresponding 0.0693 unit increase in carbon density. This finding remains robust after replacing core variables, excluding special samples, and adopting instrumental variables. Second, the impact of the industrial-favoring land allocation strategy has a significant positive spatial spillover effect on neighboring cities. Third, economic output growth, industrial structure pollution, and energy intensity are possible channels. Finally, the impact is heterogeneous. Specifically, the carbon emission effect of the industrial-favoring land allocation strategy is more pronounced in cities in western China, cities with more construction land, and cities with less developed markets. Our study contributes to a profound understanding of the impact of land allocation on climate change and sustainable development.