The invention discloses a lift car sill. The lift car sill comprises a sill body, a foot protecting plate, straight steel flat, variable steel flat and a groove-shaped frame. The groove-shaped frame is installed on the bottom face of the sill body and is of a U-shaped structure. An opening of the groove-shaped frame faces downwards. The foot protecting plate is fixedly installed at the front end of the lower portion of the groove-shaped frame and comprises vertical plates and an inclined plate. The vertical plates are fixedly installed at the front end of the lower portion of the groove-shaped frame. The inclined plate is integrally arranged on the bottom faces of the vertical plates. The variable steel flat is fixedly installed on the inner side of the lower portion of the groove-shaped frame and comprises vertical steel and inclined steel. The front end face of the vertical steel is fixedly connected with the rear end faces of the vertical plates. The front end face of the inclined steel is fixedly connected with the rear end face of the inclined plate. The top end of the straight steel flat is fixedly installed at the rear end of the lower portion of the groove-shaped frame. The bottom end of the straight steel flat is fixedly installed at the rear end of the lower portion of the inclined steel. The problems that an existing sill climbing structure is complex, not firm enough and cumbersome, resources are wasted, elevator loads are increased, and the energy and resource saving requirement which is advocated at present is not met are solved.