In a multi-regional integrated energy system (MIES), optimal scheduling under random renewable supply and user demand is crucial to promote the process of carbon neutrality. Further, the total carbon emission of multiple regions is expected to strictly restricted under a threshold, while intensifying the complex coupling of multiple agents. To address the optimal dispatching problem, we establish a typical MIES model with the global carbon emission constraint, which is formulated as a partially observable Markov decision-making process (POMDP). Then we propose an improved multi-agent deep dete...