A golf bag cart foldable device includes a bottom cart stand having a link segment. The bottom cart stand is provided with a channel, for sliding by a slider. The bottom cart stand joins a front wheel. An upper cart stand is in pinned connection with the link segment. A rear wheel frame is in pinned connection with the link segment and to a rear wheel. A linkage is connected between the slider and the upper cart stand. A strut bar is connected between the slider and the rear wheel frame. An interlocking mechanism includes a pull handle and a clamping rod having two ends lodged in the long trough. A connection member has two ends connected to the two ends of the clamping rod. A spring is joined to the clamping rod and the upper cart stand.