The invention provides a back-clamped mobile terminal with infrared meter reading and bar code scanning and a working method thereof, and relates to the field of electricity marketing. An electricity employee manually inputs data while handling electricity marketing business, and in the process, errors can be caused easily and the working efficiency is low. The back-clamped mobile terminal comprises a housing, a power source, a lighting lamp, a storer, a processor, an infrared meter reading module and a bar code scanning module, wherein a mobile terminal receiving cavity is formed in the middle part of the housing; the upper edge of the housing is bent inwards; a data power plug is arranged on the right sidewall of the mobile terminal receiving cavity; the housing comprises a main housing and a movable housing; the movable housing is arranged at the left top of the main housing and in a transverse U shape; slide fasteners are arranged at the opening of the mobile housing, and sliding holes are formed in the main housing; a data power socket is arranged on the outer side of the main housing; the main housing comprises an upper housing and a lower housing. The back-clamped mobile terminal with infrared meter reading and bar code scanning reliably guarantees the accuracy of electricity marketing business, and avoids errors easily occurring in a manual recording process and a process of manually entering in a marketing system.