A control method includes, after determining a target device to be controlled, a host sends indication information, a control command, and an address of a register of the target device to a control device through an Inter-Integrated Circuit (I2C) interface, so that the control device encapsulates the indication information, the control command, and the address of the register of the target device, and sends the indication information, the control command, and the address of the register of the target device that are encapsulated to a slave device connected to the control device.