The invention discloses a charging method and device capable of achieving active protection in a multi-gun charging mode of an electric car. The charging method comprises the steps that according to comparison relation between obtained values of charging voltage and/or charging currents fed back by a battery management system (BMS) of the electric car which is connected with a main charger and serves as a target car, and obtained values of charging voltage and/or charging currents output by all charging guns, whether the charging guns of all chargers are connected to the target car or not is judged through a monitoring module of the main charger; if yes, connection is normal, all the charging guns continue outputting charging electric energy required by charging of the target car till the charging finishing condition is met; and if not, connection is abnormal, the monitoring module of the main charger outputs a turn-off control signal to control a power module to stop charging and outputs warning information. According to the charging method and device, misoperation that multiple gun heads are connected with different electric cars in the multi-gun charging mode is recognized in time, charging output is turned off, and potential safety hazards are avoided.