A seat and seatback linkage mechanism includes: a pipe, a side bracket assembly, a seat, a seatback and driving source. The side bracket assembly includes a first side bracket and a second side bracket, and the pipe is mounted on the first and second side brackets. The seat is disposed between the first and second side brackets and includes a bottom surface, the bottom surface includes two first connecting portions and two second connecting portions, and the first connecting portions are pivotally connected to the first and second side brackets, respectively. The seatback is disposed between the first and second side brackets and connected to the second connecting portions of the seat, so that the seatback and the seat are drivingly connected to each other. The driving source is connected to one end of the seatback that is adjacent to the pipe to drive the driven end to move.