Disclosed are a block chain-based transaction processing method and system, an electronic device, and a storage medium. A plurality of parallel block chain networks having the same participant is constructed for one single block chain network, and a transaction distribution control system is constructed for each participant of the block chain network. The method comprises: when a user initiates a transaction request to a participant in the block chain network, the transaction distribution control system of the participant obtains preset type transaction parameters of the transaction request, and determines, according to the pre-stored transaction distribution control parameters, an identifier of a parallel block chain network corresponding to the preset type transaction parameters on the basis of a predetermined analyzing rule; and the transaction distribution control system of the participant uses the parallel block chain network corresponding to the determined identifier as a target block chain network executing the transaction request, and sends transaction parameters corresponding to the transaction request to the target block chain network for transaction process. The present invention improves the stability and efficiency of transaction process.