The present invention aims to provide a safe mattress which prevents the osteogenesis imperfecta patient from pressing the arm to fracture when turning over. The safe mattress comprises a bottom plate and a top plate, a longitudinal beam in the middle of the top wall of the bottom plate in the front-rear direction, the top plate is hinged at the top end of the longitudinal beam in the middle of the bottom wall, and the top plate is turned over around the top end of the longitudinal beam when one side of the top plate is pressed to turn over downward. The patient sleeps on the safe mattress in a
supine position, and if the patient turns over to the left side, the weight of the body will mainly press on the left side of the top plate, the left side of the top plate will turn over downward, the longitudinal beam will make the right side of the top plate turn up to support the right side of the back of the patient, and the right side of the top plate will share part of the weight of the body for the left arm of the patient, so that the left arm is not easy to fracture. The patient turns over to the right side, and the same principle applies, which is not described here.