Inclusion Criteria:

- informed consensus of patients

- be able to receive oral administration

- from 18 to 70 years old

- be proven to be primary adenocarcinoma of gastric cancer and staged II or III by
pathological evidences

- without other chemotherapy and/or radiation against to the disease

- normal function of other organs including heart,liver ,kidney and so on

- Eastern Cooperative Oncology Group performance status:0~2

Exclusion Criteria:

- history of other malignancy

- allergic reaction to S-1 or oxaliplatin

- be enrolling in other clinical trials

- abnormal GI tract function

- dysfunction of other organs

- female in pregnancy or lactation,or refuse to receive Contraception measures during
chemotherapy

- other situation to be judged not adaptive to the study by investigators