An automatic walking robot, comprising a housing (10), a front wheel (12a, 12b), a rear wheel (14a, 14b) and a belt drive system, the belt drive system comprising a driving wheel (16), a driven wheel (18) and a drive belt (19), the axes of the driving wheel (16) and the driven wheel (18) defining a plane, the belt (19) comprising first and second sides； the robot further comprises first and second tensioning mechanisms (20, 46) for tensioning the first and second sides respectively, the first tensioning mechanism (20) comprising a first mounting seat (22), a first drive member (24) and a first tensioning device (26) abutting against the first side, the first drive member (24) being operable to rotate so as to drive the first tensioning device (26) to move relative to the housing (10), the second tensioning mechanism (46) comprising a second mounting seat (48), a second drive member (50) and a second tensioning device (52) abutting against the second side, the second drive member (50) being operable to urge the second tensioning device (52) to move relative to the housing (10), the first and second drive members (24, 50) being located on the same side of the plane. The automatic walking robot is easy to operate and has a better tensioning effect. Also disclosed is a belt drive system.
