The invention belongs to the technical field of automobiles and relates to a passenger protecting device. The passenger protecting device comprises a vehicle speed sensor, a controller, a front range radar, a front air bag, a high-pressure air tank, connecting tubes, control valves, a rear range radar, a rear air bag and a vehicle top air bag, wherein the vehicle speed sensor is installed on a front axle, the front range radar and the front air bag are both installed in the front of a vehicle body, the rear range radar and the rear air bag are both installed in the front of the vehicle body, the vehicle tope air bag is installed on the top of the vehicle body, the high-pressure air tank is installed on a chassis of the vehicle body, the control valves are installed on the connecting tubes, and the controller is connected with the vehicle speed sensor, the range radars and the control valves through wiring harnesses. According to the passenger protecting device, when the controllers monitors that the front or the tail of an automobile is about to collide with other automobiles, the control valves are opened and used for inflating the front air bag and the rear air bag, and therefore impacting loss can be reduced. The passenger protecting device is reasonable in structure, simple in design and applicable to design of automobile anti-collision systems.