A lane departure warning method, comprising: a warning area calculation step in which a warning area for lane departure of a vehicle is calculated based on information about the vehicle and information around the vehicle; a decision making step in which a current position of the vehicle is compared with the warning area calculated in the warning area calculation step, to determine whether the vehicle is located in the warning area and output a decision instruction; and a warning step in which a warning action is performed based on the decision instruction, wherein the warning area calculation step comprises: a departure value calculation substep for obtaining a departure value of a lane line, which is a departure value calculated based on a transverse acceleration of the vehicle, or is a departure value calculated based on a staying time of the vehicle, or is a sum of the departure value calculated based on the transverse acceleration of the vehicle and the departure value calculated based on staying time of the vehicle; and a warning area modification substep in which the original lane line is modified based on the departure value of the lane line calculated in the departure value calculation substep, to obtain a modified lane line, and an area defined by the modified lane line is used as the warning area for lane departure of the vehicle. a warning area calculation step in which a warning area for lane departure of a vehicle is calculated based on information about the vehicle and information around the vehicle; a decision making step in which a current position of the vehicle is compared with the warning area calculated in the warning area calculation step, to determine whether the vehicle is located in the warning area and output a decision instruction; and a warning step in which a warning action is performed based on the decision instruction, wherein the warning area calculation step comprises: a departure value calculation substep for obtaining a departure value of a lane line, which is a departure value calculated based on a transverse acceleration of the vehicle, or is a departure value calculated based on a staying time of the vehicle, or is a sum of the departure value calculated based on the transverse acceleration of the vehicle and the departure value calculated based on staying time of the vehicle; and a warning area modification substep in which the original lane line is modified based on the departure value of the lane line calculated in the departure value calculation substep, to obtain a modified lane line, and an area defined by the modified lane line is used as the warning area for lane departure of the vehicle. a departure value calculation substep for obtaining a departure value of a lane line, which is a departure value calculated based on a transverse acceleration of the vehicle, or is a departure value calculated based on a staying time of the vehicle, or is a sum of the departure value calculated based on the transverse acceleration of the vehicle and the departure value calculated based on staying time of the vehicle; and a warning area modification substep in which the original lane line is modified based on the departure value of the lane line calculated in the departure value calculation substep, to obtain a modified lane line, and an area defined by the modified lane line is used as the warning area for lane departure of the vehicle.