A stroller, comprising a stroller frame with an unfolded state and a folded state, a front wheel assembly disposed at front of a bottom of the stroller frame, a rear wheel assembly disposed at rear of a bottom of the stroller frame, and a lock mechanism for locking the stroller frame in the unfolded state, the stroller frame comprising two side supports respectively disposed on left and right sides, and a transverse brace assembly connected between the side supports on two sides, is characterized in that, the side support on each side comprises a front support, a rear support, a push rod and an upper supporting rod each extending along an up-down direction, an upper portion of the front support and an upper portion of the rear support are pivotally connected with each other, and a lower portion of the upper supporting rod is pivotally connected with the upper portion of the front support or is pivotally connected with the upper portion of the rear support; or the upper portion of the front support and the lower portion of the upper supporting rod are pivotally connected with each other, and the upper portion of the rear support is pivotally connected with the lower portion of the upper supporting rod; or the upper portion of the front support, the upper portion of the rear support and the lower portion of the upper supporting rod are pivotally connected with each other around a same center line of rotation, and an upper portion of the upper supporting rod is pivotally connected with a lower portion of the push rod; the side support on each side further comprises an upper connecting rod, a rear connecting rod, a lower connecting rod, and a sliding member disposed on the rear support capable of sliding up and down along a length extension direction of the rear support, wherein, an upper portion of the upper connecting rod is pivotally connected to the push rod, one end portion of the lower connecting rod is pivotally connected to the front support, and the other end portion of the lower connecting rod is pivotally connected with the sliding member, and when the stroller frame is folded, the sliding member slides downwardly along the rear support, and the upper supporting rod is rotated backward and folds up on a rear side of the rear support, characterized in that the rear connecting rod is pivotally connected to the upper supporting rod, one end portion of the rear connecting rod is pivotally connected with the sliding member, U the other end portion of the rear connecting rod is pivotally connected with a lower portion of the upper connecting rod. a stroller frame with an unfolded state and a folded state, a front wheel assembly disposed at front of a bottom of the stroller frame, a rear wheel assembly disposed at rear of a bottom of the stroller frame, and a lock mechanism for locking the stroller frame in the unfolded state, the stroller frame comprising two side supports respectively disposed on left and right sides, and a transverse brace assembly connected between the side supports on two sides, is characterized in that, the side support on each side comprises a front support, a rear support, a push rod and an upper supporting rod each extending along an up-down direction, an upper portion of the front support and an upper portion of the rear support are pivotally connected with each other, and a lower portion of the upper supporting rod is pivotally connected with the upper portion of the front support or is pivotally connected with the upper portion of the rear support; or the upper portion of the front support and the lower portion of the upper supporting rod are pivotally connected with each other, and the upper portion of the rear support is pivotally connected with the lower portion of the upper supporting rod; or the upper portion of the front support, the upper portion of the rear support and the lower portion of the upper supporting rod are pivotally connected with each other around a same center line of rotation, and an upper portion of the upper supporting rod is pivotally connected with a lower portion of the push rod; the side support on each side further comprises an upper connecting rod, a rear connecting rod, a lower connecting rod, and a sliding member disposed on the rear support capable of sliding up and down along a length extension direction of the rear support, wherein, an upper portion of the upper connecting rod is pivotally connected to the push rod, one end portion of the lower connecting rod is pivotally connected to the front support, and the other end portion of the lower connecting rod is pivotally connected with the sliding member, and when the stroller frame is folded, the sliding member slides downwardly along the rear support, and the upper supporting rod is rotated backward and folds up on a rear side of the rear support, characterized in that the rear connecting rod is pivotally connected to the upper supporting rod, one end portion of the rear connecting rod is pivotally connected with the sliding member, U the other end portion of the rear connecting rod is pivotally connected with a lower portion of the upper connecting rod.