With the development of the active distribution system (ADS) and multi-microgrids (MGs), increasing numbers of distributed energy resources are connected to distribution networks (DNs) using MGs. The competition between DN and MGs brings a huge challenge to efficient power system dispatching. For the strong decentralized and autonomous characteristic of ADS, this paper proposes an autonomous optimization model of the active distribution system with MGs based on analytical target cascading theory (ATC). DNs and MGs are regarded as topics of different interest. Based on their detailed models, ATC theory is proposed to decouple the dispatching of DNs and MGs by modeling the tie-line flow as a pseudo-generator/load, so that MGs and DNs can autonomously utilize their distinct resources to optimize their operation and economic benefits. Various uncertain factors are also considered by using chance-constrained programming. A modified IEEE 33 system and an actual regional DN are studied to show the effectiveness of the proposed algorithm. (C) 2018 Elsevier Ltd. All rights reserved.