A vehicle charging device and a method applied to the device are disclosed. The device includes a transformer and two impedance tuners. One side of the transformer has two communication wires to couple with an electric vehicle. Each of the two impedance tuners is connected in parallel to one of the two communication wires. The two impedance tuners are configured to regulate reactance characteristics of the two communication wires. Therefore, the impedance of the communication wires can be gradually regulated in response to the signal strength, such that the vehicle charging device and the electric vehicle communicate in a state approaching impedance matching to prevent charging abnormalities caused by an excessively high bit error rate in data exchange.
