NOVELTY - The method involves confirming a reference of a charging reservation time input to a controller. A wake-up time is set based on the reference confirmed in the step of confirming the reservation reference. A charging is started after a vehicle wakes up at the time of reaching the wake-up time set in the step of setting the wake-up time. Confirmation is made to check whether a charging reservation time is a reference of a departure time or a reference of a start time. The charging is ended (S700) when the charging is completed.    USE - Charging method for green car for reserving and charging high voltage battery.    ADVANTAGE - The charging method of green car which reduces an error in charging time by a charging prediction time depending on a state of a high voltage battery at the time of prediction charging and calculating a charging prediction time in consideration of a state of a charger. Even though the reservation charging is set, when the charger is connected to the vehicle, the charging is attempted for a set period of time in the initial stage of the connection to determine chargeable capacity of the charger, thus more clearly and predicting a charging completion time. The vehicle wakes up and is charged at the derived time by accurately predicting and applying the charging prediction time and the wake-up time based on the information obtained from the charger connected to perform the reservation charging. The consumer satisfaction, the fuel efficiency, and the brand image are improved by interrupting the insufficient charging which is caused by waking up later than the prediction time and a dark current which is consumed by waking up earlier than the prediction time.    DESCRIPTION OF DRAWING(S) - The drawing shows a charging method for a green car.    Step for determining whether reservation reference is equal to departure time (S100)    Step for determining whether charger is connected (S310)    Step for measuring chargeable voltage and current (S330)    Step for waking-up and charging (S500)    Step for ending charging (S700)