Prognosis for patients with early gastric cancer is relatively favorable, however some of them with negative lymph nodes will still die from either postoperative recurrence or distant metastases. Some researchers proposed that lymph node micrometastasis is a potential cause for recurrence and metastasis in these patients. Detection of lymph node micrometastasis is more difficult compared to that of macroscopic lymph node metastasis, and its impact on prognosis of gastric cancer remains controversial. The authors, in this paper, address the research progress in lymph node micrometastasis of gastric cancer.