A baby stroller, comprising: an independent stroller frame including a rotatable base; and a detachable chair, wherein when the baby stroller is unfolded, the base abuts and positions the stroller frame automatically, and when the baby stroller is folded, the chair is rotated together with the base, such that the chair can be folded and positioned together with the stroller frame directly; the chair includes a fabric seat, upper and lower tubes (42, 43) mounted onto the seat, and a chair folding joint installed between the seat and the upper and lower tubes, wherein the chair folding joint comprises: an upper joint (61, 71), fixed to the bottom of the upper tube of the seat, and having a notch (611, 711) formed on an external side of the upper joint; a fixing member (62, 72), installed into the notch of the upper joint through a spring (69, 73); a lower joint (64, 74), fixed at an upper end of the lower tube of the seat, and having a positioning slot (641, 741) formed on an internal side of the lower joint and corresponding to the fixing member; a press button (66, 76), installed on an external side at the upper tube of the seat, and having a slide member (67, 77) coupled to the bottom of the press button; and a link element (68, 78), installed in the upper tube of the seat, and being configured to link an actuation of the press button with folding the chair. an independent stroller frame including a rotatable base; and a detachable chair, wherein when the baby stroller is unfolded, the base abuts and positions the stroller frame automatically, and when the baby stroller is folded, the chair is rotated together with the base, such that the chair can be folded and positioned together with the stroller frame directly; the chair includes a fabric seat, upper and lower tubes (42, 43) mounted onto the seat, and a chair folding joint installed between the seat and the upper and lower tubes, wherein the chair folding joint comprises: an upper joint (61, 71), fixed to the bottom of the upper tube of the seat, and having a notch (611, 711) formed on an external side of the upper joint; a fixing member (62, 72), installed into the notch of the upper joint through a spring (69, 73); a lower joint (64, 74), fixed at an upper end of the lower tube of the seat, and having a positioning slot (641, 741) formed on an internal side of the lower joint and corresponding to the fixing member; a press button (66, 76), installed on an external side at the upper tube of the seat, and having a slide member (67, 77) coupled to the bottom of the press button; and a link element (68, 78), installed in the upper tube of the seat, and being configured to link an actuation of the press button with folding the chair. an upper joint (61, 71), fixed to the bottom of the upper tube of the seat, and having a notch (611, 711) formed on an external side of the upper joint; a fixing member (62, 72), installed into the notch of the upper joint through a spring (69, 73); a lower joint (64, 74), fixed at an upper end of the lower tube of the seat, and having a positioning slot (641, 741) formed on an internal side of the lower joint and corresponding to the fixing member; a press button (66, 76), installed on an external side at the upper tube of the seat, and having a slide member (67, 77) coupled to the bottom of the press button; and a link element (68, 78), installed in the upper tube of the seat, and being configured to link an actuation of the press button with folding the chair.