Abstract: To achieve the coordinated development of the water-energy-food-carbon system under Carbon Neutrality in the Beijing-Tianjin-Hebei region, a three-dimensional water-energy-food-carbon security assessment model is constructed. This model considered the reliability within individual systems, coordination between dual systems, and sustainability among multiple systems. In this paper, an improved CRITIC method was utilized to assess the security level of the water-energy-food-carbon system in the Beijing-Tianjin-Hebei region from 2000 to 2022, the changes in system security before and after the inclusion of carbon emission indicators in the water-energy-food system was analyzed, and the obstacles identification in the water-energy-food-carbon system was done. The results indicate an increasing trend in the security level of the water-energy-food coupling system in the Beijing-Tianjin-Hebei region from 2000 to 2022, with the average value rising from 0.354 to 0.535, while the security level of the water-energy-food-carbon system changed to 0.508 in 2022 after the carbon emissions were included in the system. After the implementation of the Carbon Neutrality policy in 2020, the system security was improved to a certain extent. Factors such as energy production elasticity coefficient, food yield fluctuation index, difference between food exports and imports, number of civilian vehicles and proportion of hydroelectricity generation collectively emerge as the primary obstacle factors affecting the security of the water-energy-food-carbon system in the Beijing-Tianjin-Hebei region.