The invention provides a method and a device of drawing a 2D map, and a storage device. The method comprises steps that a continuous depth image sequence is acquired; a detection window used for detecting obstacles is established in a depth image, and the position of the detection window relative to a robot is fixed, and the cross section of the detection window vertical to the advancing direction of the robot is at least greater than the projection of the robot on the cross section; depth information in the detection window is acquired; whether the obstacles occur is determined; when the obstacles occur, an obstacle boundary line is drawn according to obstacle depth information, and the passable area and the impassable area of the advancing plane of the robot are discriminated from each other; the direction of the robot is adjusted to traverse the scene of the robot, and the 2D map of the scene is formed. The device comprises a processor and at least one depth camera. The storage device is used to store program data, which is used to implement the above mentioned method. According to the invention, the 2D map can be drawn under a condition of less and simple data.