A double data rate dual-in-line memory module (DDR DIMM), a memory system and an operation method thereof using a data buffer for error correction are disclosed. In an example, the DDR DIMM includes a first channel including a first group of DRAM chips and a first data buffer corresponding to the first group of DRAM chips; wherein: the first data buffer is configured to obtain all write data signals input to the first channel, encode write data of all the write data signals to generate a first ECC, and send the first ECC and the write data to the first group of DRAM chips in a write operation. The disclosure can realize excellent error detection and error correction within the memory module and can greatly reduce bit error rate of the entire memory module.