A collapsible high chair frame including a supporting stand, a seat, a connecting device and a positioning device. The supporting stand is provided with a rear and a front supporting leg which are foldable toward each other. The seat has a base and a back which are connected pivotally to each other. The connecting device is pivotally coupling to the supporting stand and the seat. According to the configuration of this invention, the connecting device is rotatable by releasing a lock on the positioning device which is arranged between the connecting device and the seat, meanwhile, the rear supporting leg is closed up to the front supporting leg and also folded toward the base and back of the seat at the same time. The collapsible high chair can be stored with a compact frame.