The immigrants, including 45 men and 14 women, were caught on July 29 when they were on a bus to travel to different Chinese cities.
They were alleged to have climbed mountains to reach the Chinese border, state-run Xinhua news agency reported.
There were 75 people aboard the bus, which had a designed capacity of 52 passengers.
Fifty nine of them were Vietnamese without legal entry permits, the report quoted police as saying.
They included two couples, two brothers and a mother and son. The youngest of the them was 18 years old. Thirty-two of them were born after 1990.