A lockable pressure adjustment seat of a fitness apparatus includes a base, a seat back, and an adjustment unit. The base is disposed with a slide track and a locating hole. The seat back is pivotally connected to the base. The seat back includes an extension rod. One end of the extension rod is linked and fixed to the seat back. A through hole is disposed adjacent to the other end of the extension rod. The adjustment unit includes a lever, a pressure bar, and a locking set. The lever penetrates the slide track. The pressure bar includes a push rod and a fixation base. The push rod holds against the lever. The fixation base is secured to the other end of the extension rod. The locking set is fixed to the fixation base, and comprises an elastic member and a locating rod.