The invention relates to a rail transit adjusting seat. The rail transit adjusting seat comprises a base, a backrest and a supporting plate, wherein the backrest is fixed on the base, and the supporting plate is fixed to the backrest; a V-shaped rod and two slide rails are fixed on the supporting plate; a seat cushion is mounted on the two slide rails; the seat cushion comprises a seat cushion body, a supporting rod and two slide blocks, wherein the supporting rod is hinged at the bottom end of the seat cushion body; and the two slide blocks correspondingly move along the two slide rails. According to the rail transit adjusting seat, the structure is simple; the use is convenient; the seat cushion body can move outwards for a section of distance under the cooperation of the slide rails andthe V-shaped rod so that the distance between the outermost end of the seat cushion body and the backrest can be increased to enable two persons to sit on one seat cushion body; and therefore, the phenomenon of lacking seats is relieved, and the adjusting is convenient and fast; and meanwhile, the seat cushion body can retract back when it is not during morning peak.