An adjustment bracket structure for a front upright of an exercise bicycle comprises a bicycle frame and the front upright, wherein a supporting component extending towards the front upright is fixed to the bicycle frame, and the lower end of the front upright is pivoted to the supporting component through a rotary shaft; a bracket component capable of being clamped on the supporting component is arranged on the front upright, and bracket parts matched with the bracket component are arranged on the supporting component in the swinging direction of the front upright. The front upright is angle-adjustable, thereby convenient for users with different heights and arm lengths. The bracket component is of strength-saving structure and utilizes the lever principle, thereby being more convenient to operate. All components are structurally reliable and connected firmly and stably, and thus more convenient to use on the premise of guaranteeing safety and stability.