A method and circuit for reducing SATA (Serial Advanced Technology Attachment) transmission data errors by adjusting the period of sending two consecutive ALIGN Primitives. The method reads a counting value of an 8b/10b coding error counter at a predetermined period and adjusts the period of sending two consecutive ALIGN Primitives according to the counting value. Because the system dynamically adjusts the period of sending two consecutive ALIGN Primitives according to the channel condition, the SATA transmission data errors can be reduced.