In order to deeply explore the potential of flexible resources of active distribution etwork in response to carbon emission reduction, an optimal operation method of active distribution network with flexible resources is established considering the participation of active distribution network in carbon emission market transactions. The management model and transaction mechanism model of active distribution network participating in carbon trading market are established. The objective function of the optimal operation model is constructed by minimizing the unit output cost, flexible resource call cost, power purchase cost and carbon transaction cost (benefit). The optimization model is established by taking into account the necessary constraints such as carbon trading limit constraint, power balance constraint, active distribution network operation constraint, energy storage equipment operation constraint and flexible resource call constraint. Two measures are introduced to improve the sparrow search algorithm. One is to use adaptive security value and the other is to introduce chaotic search into the transfer process under the unsafe state of the discoverer. The improved sparrow search algorithm is used to design the solution process of the optimal operation model. Finally, based on the established model, the operation scheme, carbon trading scheme and operation index of the active distribution network in a park are analyzed in three scenarios, and the effectiveness of the established model is verified, which can fully reduce the comprehensive operation cost and reduce the carbon emission level.