The invention relates to a split-type car seat back structure which comprises a back upper-end framework, a back lower-end framework, a first rotating buffer device and a second rotating buffer device. According to the technical scheme, an entire seat back is replaced by the back upper-end framework and the back lower-end framework through an improvement; the rotating buffer devices are arranged between the back upper-end framework and the back lower-end framework; the back lower-end framework is equipped with a deformable structure, so that the energy-absorbing space between the seat back anda passenger can be sufficiently utilized through the backward rotating motion of the back lower-end framework, the buffer energy-absorbing effect of torsion springs can be achieved, and the collisionimpact between the passenger and a seat can be reduced; through the backward movement of the back lower-end framework of the seat, the uniform rigid contact between the back of the passenger and theentire framework of the seat back can be facilitated, and the stress on the back of the passenger can be dispersed to the greatest extent; and by the adoption of the split-type car seat back structure, not only can the driving comfort of the passenger be guaranteed, but also the car safety can be improved.