A data transaction method between control chips. Data buffers of the control chips of the control chipset have fixed size and amount. In addition, read/write acknowledge commands are asserted in sequence according to read/write commands, by which the control chips can detect the status of the buffers within another control chips. When a control chip asserts a command, the corresponding data must be ready in advance. Therefore, the signal line for providing the waiting status, data transaction cycle and stop/retry protocol can be omitted. Accordingly, commands or data can be continuously transmitted without waiting, stop or retry, the performance is improved.