A chair back structure is disclosed and includes a chair back that includes a frame, an upper support pad coupled to an upper portion of the frame, and a lower support pad arranged at a lower end of the upper support pad, and an elastic connection piece connecting the upper support pad and the lower support pad to each other. The upper support pad includes a lower support pad coupling seat. The lower support pad includes an upper support pad coupling seat. The elastic connection piece has an upper end mounted to the lower support pad coupling seat of the upper support pad and a lower end mounted to the upper support pad coupling seat of the lower support pad, so that the lower support pad is provided with elasticity and movability by means of the elastic connection piece.