The purpose of the article is to model the ecological system in the circular economy model. To realize the goal, the method of mathematical modeling was used when creating models of the ecological system. It is proposed to understand under the ecological system the logistics system as a set of elements-links interconnected in the process of managing the movement of direct and reverse logistics flows, which takes into account the eco-destructive impact on the environment. An ecological system, like any system, has the following properties: integrity, divisibility, organization, structuredness, integrability, emergentity, purposefulness. In addition, the ecological system has properties typical for the logistics system: complexity, openness, stochasticity, heterogeneity and multifunctionality, dynamism and adaptability. The ecological system also has specific characteristics: environmental friendliness, closedness. The ecological system is considered at the micro, meso and macro levels. At the micro level, the elements of the ecological system are the functional units of the organization's logistics, including the unit responsible for reverse logistics. At the meso- and macro-levels, the ecological system is represented by the enterprises - participants of the logistics chain. The analysis of logistics specialists research allowed us to identify the following approaches to modeling the ecological chain: organizational, flow, process. The main difference between the approaches is the understanding of the essence of the chain and the elements that make it up. A necessary condition for the successful functioning of the ecological chain is the coordination of the principles of process and flow approaches. It is proposed to form chains of processes according to the direction of flow. In this case, the logistics process is considered as an element of the value creation process. Ecological system modeling based on the use of the reverse logistics model was improved, which covers not only the collection and transportation of materials and goods, but also value-added activities such as testing, sorting, recovery, recycling and redistribution and is a major factor contributing to the expansion of implementation approaches to the circular economy in various branches of the national economy.