The invention discloses a lane-changing control method and device for a car and a storage medium, and belongs to the technical field of vehicle engineering. The method comprises the following steps: performing blind area detection on the car after the car ignites; when a dangerous car does not exist in a blind area of the car, confirming whether the car is in a self-adaptive cruising mode or not if a steering instruction is received; and when the car is in the self-adaptive cruising mode, controlling the car to perform lane-changing through an automatic lane-changing function of the car. The lane-changing control method can detect the blind area of the car, controls the car to automatically perform lane-changing while receiving the steering instruction and the automatic cruising mode is started, improves a condition that the dangerous car in the blind area of the car cannot be observed before the driver changes the lane, improves complex operation of manually performing lane-changing by the driver, relieves workload of the driver, improves car lane-changing efficiency and safety, and reduces occurrence possibility of a traffic accident.