1. When setting wifi network access, the operation is not correct, and the wifi network is not connected, thus using the mobile Internet traffic;
2, some programs only support the use of 3G network download, can not be downloaded in WIFI network;
3, may be the location of the WIFI signal is unstable, resulting in the use of 3G network for Internet access, it is recommended to turn off cellular data or mobile phone Internet access, to ensure that real-time understanding of what network is used (WIFI or 3G);
4, due to the time limit of some WIFI signals, the network will be automatically disconnected after the arrival time and use the 3G network to reconnect;
5, because some software supports breakpoint reconnection, so when the WIFI signal is unstable, it will automatically download software through the 3G network. Tips: In order to avoid mobile data charges, it is recommended to turn off the data connection when using WIFI Internet access.