Gastric cancer is one of the most common cancers and the efficient therapeutic methods are limited. Further study of the exact molecular mechanism of gastric cancer to develop novel targeted therapies is necessary and urgent. We herein systematically examined that miR-204 suppressed both proliferation and metastasis of gastric cancer AGS cells. miR-204 directly targeted SOX4. In clinical tissue research, we determined that miR-204 was expressed much lower and SOX4 expressed much higher in gastric cancer tissues compared with normal gastric tissues. Associated analysis with clinicopathological parameters in gastric cancer patients showed miR-204 was associated with no lymph node metastasis and early tumor stages whereas SOX4 was associated with lymph node metastasis and advanced tumor stages. In addition, miR-204 and SOX4 were negatively correlated in tissues from gastric cancer patients. Our findings examined the important role of miR-204 and SOX4 played in gastric cancer, and they could be used as candidate therapeutic targets for gastric cancer therapy.