The invention provides a device for improving safety of people in a car. The device comprises a car body, car doors, a protecting mechanism and a control mechanism, wherein the protecting mechanism comprises a bearing board, supporting rods, a driver, buffering nets, an air-filling bag and an air-filling machine; a sliding groove is formed in the car body, and the supporting rods are movably mounted on the sliding groove; the bearing board is provided with a plurality of breaking marks on one side, close to the wall of the car body, of the corresponding supporting rod; the driver is in drive connection to the supporting rods and can drive the supporting rods to move close to or far away from the wall of the car body; the buffering nets are mounted in the car body and positioned below the supporting rods; the air-filling bag is mounted in the car body and positioned below the buffering nets; the air-filling machine communicates with the air-filling bag through a pipeline; the control mechanism comprises a controller, a speed sensor and a gravity sensor. According to the device, more impacting force on the people in the car body can be absorbed as the impacting force increases during the car falling, so that the people in the car can be effectively protected.