The invention discloses a mobile terminal and a back cover plate thereof. The back cover plate comprises a substrate, wherein an ink layer is arranged on the first surface of the substrate; a sensor layer is arranged on the surface of the ink layer; a circular hole is formed in the substrate; a cursor control component is arranged in the circular hole; the bottom of the cursor control component is in direct contact with the sensor layer, and the top of the cursor control component is higher than the plane height of the substrate; the sensor layer comprises a plurality of partitions connected with an integrated circuit through wires respectively; the cursor control component is in contact with different partitions to generate corresponding voltage signals when rolling operation is carried out by a user on the cursor control component, so that the moving direction and distance of a cursor on the screen of a terminal are controlled. According to the mobile terminal and the back cover plate thereof provided by the invention, a cursor control function can be integrated on the back cover plate, so that any area on the screen can also be controlled when the user performs one-handed operation, convenience is provided for the user, and the user experience is promoted.