A child seat includes a seat portion fixedly connected with a first coupling part, a connector that is pivotally connected with the first coupling part of the seat portion and is operable to detachably engage with a corresponding structure provided on a child supporting apparatus, a locking mechanism operable to lock and unlock the connector with respect to the seat portion, and a backrest frame fixedly connected with a second coupling part and operatively connected with the locking mechanism, the second coupling part being pivotally connected with the first coupling part, wherein the backrest frame is rotatable in a folding direction to cause the locking mechanism to unlock the connector with respect to the seat portion and in an unfolding direction to cause the locking mechanism to lock the connector with respect to the seat portion.