The invention discloses a network control method and device for a vehicle-mounted intelligent system, the vehicle-mounted intelligent system and a vehicle. The method comprises the following steps of sending a network efficiency detection request to a set server when all networks of the vehicle-mounted intelligent system are started; judging a network connection condition efficiency score of each network card; determining a network that needs to be started and used according to the network connection condition efficiency scores and disconnecting other network connections, wherein when the vehicle-mounted intelligent system selects the network whose score is higher than Ethernet to establish a connection according to a network scoring mechanism, the network with the highest score is normally connected, and meanwhile, if the disconnected network is the Ethernet, the Ethernet is not disconnected, the Ethernet is allowed to start normally and stays connected; and when the Ethernet is directly started, a process of network scoring is skipped to start an Ethernet card directly. Through modifying an algorithm of the network scoring mechanism, a goal of simultaneously running two network cards of the vehicle-mounted intelligent system is realized.