The research on factors affecting customers' decision to choose a mobile network in Tra Vinh province by collecting primary data of 250 individual customers using mobile networks such as: Viettel, Vinaphone, Mobiphone, Vietnammobile in Tra Vinh province. On the basis of inheriting related studies, the authors use multivariate regression method, Research results have found 06 factors affecting the decision to choose a mobile network of customers in Tra Vinh province in order of most importance to least important: Marketing, Technology, Customer care, Usage cost, Convenience, Network quality. On that basis, the authors propose administrative implications for network company to develop better customer service policies in the future.