Disclosed is a data transfer system capable of accelerating data transmission between two chips. The data transfer system includes: a master system-on-a-chip (SoC) including a master transmission circular buffer and a master reception circular buffer; and a slave SoC including a slave reception circular buffer and a slave transmission circular buffer. The slave/master reception circular buffer is a duplicate of the master/slave transmission circular buffer; accordingly, the write pointers of the two corresponding buffers are substantially synchronous and the read pointers of the two corresponding buffers are substantially synchronous as well. In light of the above, the read and write operations of the master/slave transmission circular buffer can be treated as the read and write operations of the slave/master reception circular buffer; therefore some conventional data reproducing procedure(s) for the data transmission can be omitted and the data transmission is accelerated.