Based on the statistical sources for over 100 years, the author states some opinions about data accuracy and difficulties of the statistical work on the number of Chinese people in Vietnam. Accordingly, the number of Chinese immigrants in Vietnam has constantly increased over time, reaching the highest at the end of the 60s of the 20th century, then gradually decreased due to the war and conflicts between Vietnam and China in 1975. However, the statistical data on the number of Chinese people in Vietnam have never reflected accurately the actual situation. It is due to the fact that the immigration course of Chinese people has taken place for thousands of years, generations of Chinese people were Vietnamized and fully integrated into the Vietnamese community. In addition, the loose immigration policy of Vietnamese authorities during historical periods, as well as the French later, made the governments almost powerless against strong influx of Chinese immigrants into Vietnam, especially Southern Vietnam.