A network access method, comprising: obtaining, by a terminal, a priority of a to-be-performed first network service; determining, by the terminal according to a relationship between a network service priority and a network service class, a network service class required for performing the first network service, wherein the relationship is stored in the terminal, and the network service class is used to indicate network quality; and obtaining, by the terminal, a network service class of a first network currently accessed by the terminal, and if the network service class of the first network is lower than the network service class required for performing the first network service, accessing, by the terminal, a second network, and performing the first network service by using the second network, wherein a network service class of the second network is higher than the network service class of the first network, wherein the method further comprises: if the network service class of the first network is higher than or equal to the network service class required for performing the first network service, counting, by the terminal, a current second bandwidth occupancy rate in the first network; if the second bandwidth occupancy rate is greater than a second threshold, accessing, by the terminal, a wide area network, WAN, by simultaneously using the first network and at least one network different from the first network, in order to meet the bandwidth requirements of all the network services running in the terminal. obtaining, by a terminal, a priority of a to-be-performed first network service; determining, by the terminal according to a relationship between a network service priority and a network service class, a network service class required for performing the first network service, wherein the relationship is stored in the terminal, and the network service class is used to indicate network quality; and obtaining, by the terminal, a network service class of a first network currently accessed by the terminal, and if the network service class of the first network is lower than the network service class required for performing the first network service, accessing, by the terminal, a second network, and performing the first network service by using the second network, wherein a network service class of the second network is higher than the network service class of the first network, wherein the method further comprises: if the network service class of the first network is higher than or equal to the network service class required for performing the first network service, counting, by the terminal, a current second bandwidth occupancy rate in the first network; if the second bandwidth occupancy rate is greater than a second threshold, accessing, by the terminal, a wide area network, WAN, by simultaneously using the first network and at least one network different from the first network, in order to meet the bandwidth requirements of all the network services running in the terminal. if the network service class of the first network is higher than or equal to the network service class required for performing the first network service, counting, by the terminal, a current second bandwidth occupancy rate in the first network; if the second bandwidth occupancy rate is greater than a second threshold, accessing, by the terminal, a wide area network, WAN, by simultaneously using the first network and at least one network different from the first network, in order to meet the bandwidth requirements of all the network services running in the terminal.