The invention discloses a cross slider type sliding plug door mechanism, relates to an opening / closing and sealing mechanism of a sliding plug door for a high-speed train, and is particularly applied to opening / closing and sealing the door of a subway or the high-speed train. The cross slider type sliding plug door mechanism consists of a stepping motor, a screw rod, a screw rod nut, a support, a main shaft, a cross slider, a guide rod, a sliding plug door body, a guide wheel and a guide slot. The main shaft is fixed on the support. One hole in the cross slider matches the main shaft and can slide along the main shaft, and another hole of the cross slider perpendicular to the hole is matched with the guide rod. The sliding plug door body is fixedly coupled to the guide rod through a bolt. The guide wheel is arranged on the guide rod, and is limited in the guide slot to move. The guide slot is made into a shape of a line and a circular arc. When the guide wheel is driven by the cross slider to move along the guide slot, the guide wheel drives the sliding plug door to open and close and the sliding plug movement is realized. The movement of the cross slider is realized by driving the screw rod to rotate through the stepping motor, so the screw rod nut moves linearly, and the screw rod nut is fixedly coupled to the cross slider.