The invention provides a cluster transaction processing method for a private chain node. The method comprises the following steps of (1) performing load balance: receiving a transaction sent by an upper application layer through cluster nodes of a block chain, and loading the transaction to different transaction processing machines; (2) performing transaction check and transaction execution: receiving and checking the transaction by a load balance machine through the transaction processing machines, and after the check is passed, performing the transaction execution; (3) generating a global state tree root and a Merkle tree root; (4) constructing a block, and broadcasting the constructed block to other nodes in a block chain network; (5) after other nodes in the block network receive the block, checking the block; and (6) performing block decision consensus. By deploying a block chain function to different nodes in a cluster, the transaction execution and the block construction and consensus can be concurrently executed in the different nodes of the cluster, so that the utilization rate of computing resources is increased, the performance of a block chain system is improved, and the block chain is more suitable for a business scene of the high-frequency transaction.