Transit visa for Vietnamese passport holders

TNguyen, first 72 hours free transit doesn't apply to Vietnamese people. If your total transit in these two cities is less than 24 hours, you can enjoy 24 hours free transit without applying any entry permit in advance. Otherwise, you are required to apply for a transit type from Chinese embassy in your country in advance. It requires your flight itineraries. Usually, it provide 7 days duration of stay. It's enough for your transit in Guangzhou and Kunming.