The invention discloses a baby carriage seat packet which comprises a seat board and a backrest. Two sides of the lower part of the backrest are provided with a backrest connecting seat. The backrestconnecting seat is divided into an upper chamber and a lower chamber. A panel which corresponds with the upper chamber is provided with a seat packet detaching press button. The upper chamber is internally provided with a pin on which a pulley sleeves. The lower chamber is internally provided with a rotating disc and a fixed disc. The fixed disc is fixedly connected with the backrest connecting seat. One side of the rotating disc is rotatably connected with a rotating oblique surface of the fixed disc. The seat packet detaching press button is connected with a connecting line. The connecting line winds the pulley and is connected with the rotating disc. The rotating disc is axially connected with a pull block. The pull block is provided with a seat packet quick detaching pin. The pull block successively penetrates through the fixed disc and a frame connecting seat. The seat packet quick detaching pin penetrates through a window of a shielding plate. Seat packet detaching mechanisms arearranged at two sides of the backrest. The baby carriage seat packet has an obvious structure. A user can easily align an assembling box on the frame. Furthermore a force bearing point is almost in agravity line of the seat packet. Furthermore in detachment, easy operation is realized because the force bearing point is closer to a gravity center.