A method of processing data for a blockchain, wherein a blockchain network has a bottom blockchain network and an upper blockchain network, the bottom blockchain network has a plurality of bottom blockchain nodes, the upper blockchain network has a plurality of upper blockchain nodes, and the method is applied to the upper blockchain nodes, and the method includes: transmitting block data in a current node belonging to an upper blockchain of the upper blockchain network to a bottom blockchain node, so that each bottom blockchain node stores the block data into a bottom blockchain of the bottom blockchain network by using a consensus verification. The present disclosure also proposes a device of processing data for a blockchain, a blockchain system, a computer device and a computer readable medium.