The invention discloses an adjustable pillow structure which comprises a bracket, supporting rods, a shaft rod, trays, movable connecting rod structures and a locking structure, wherein the shaft rod is rotationally connected with the bracket; one end of each supporting rod is hinged to the corresponding tray; the other end of each supporting rod rotationally sleeves the shaft rod; one end of each movable connecting rod structure is hinged to the corresponding tray; the other end of each movable connecting rod structure is connected with shaft rod; the locking structure is connected to an end part of the shaft rod, and can be utilized for fixing the relative positions of the bracket, the supporting rods and the shaft rod. Therefore, the bracket is fixedly arranged and supports the shaft rod, so as to support the whole pillow structure, the trays are fixedly connected with a back cushion of a pillow, and perform supporting and adjustment operations by relying on the supporting rods and the movable connecting rod structures, and the positions of the trays can be adjusted up and down as well as left and right through relative rotation between the supporting rods and the shaft rod as well as between the movable connecting rod structures and the shaft rod; meanwhile, the locking structure can be utilized for fixing and locking the bracket, the supporting rods and the shaft rod at the relative positions, so as to achieve random adjustment and positioning of the pillow and the back cushion within a certain range of positions and angles; the pillow structure is simple in structure and convenient to adjust.