The utility model relates to the technical field of automobile seat, disclose a seat turnover mechanism and seat, seat turnover mechanism includes mounting bracket, connecting piece, pivot, carousel, pawl, locking piece and drive part, pivot one end is connected with mounting bracket rotation, the other end is fixed with connecting piece, carousel is connected in pivot and is equipped with first clamping part, pawl is connected with mounting bracket rotation, and pawl has first locking surface, locking piece is connected with mounting bracket rotation, and locking piece is equipped with second clamping part and second locking surface, locking piece has first position and second position, when first position, second clamping part is clamped with first clamping part, and second locking surface is abutted with first locking surface, to lock carousel and pivot, when second position, second clamping part is separated with first clamping part, and second locking surface is separated with first locking surface, to unlock carousel and pivot. The utility model can lock seat body in vertical state, make seat body neither occupy rear space, and also can vacate front space.