Leveraging the role of urban-rural integration in curbing agricultural carbon emissions intensity holds significant practical value for promoting low-carbon transitions in rural areas and advancing agricultural and rural modernization. Grounded in the theory of urban-rural integration development, this study employs a classical panel model to examine the impact of urban-rural integration on agricultural carbon emissions intensity. Using panel data spanning 2005 to 2020 from 30 provinces (cities, districts), the study delves into the mechanisms and heterogeneity of this relationship. Results reveal an ongoing upward trajectory in national and regional (eastern, central, and western) urban-rural integration development, juxtaposed with a notable decline in agricultural emissions intensity—opposite fluctuation trends. Urban-rural integration significantly dampens the intensity of agricultural carbon emissions. Further analyses spotlight a pronounced suppression of emissions intensity in the eastern region and major grain-producing areas due to urban-rural integration. Moreover, the urban-rural integration achieves this by bolstering agricultural technology advancement and scaling operations. To this end, proactive promotion of targeted urban-rural integration policies, reinforcement of agricultural technology progress and scaled operations, and recognition of emission reduction divergence are pivotal for curbing agricultural carbon emissions intensity.