The utility model relates to the technical field of straight-line cigarette sucking machines, and in particular discloses a sucking termination device of a straight-line cigarette sucking machine. The sucking termination device comprises a fixing plate and a plurality of sucking termination mechanisms, wherein the fixing plate is fixed on the straight-line cigarette sucking machine; the sucking termination mechanisms comprise cigarette clamps, light baffle covers, highlight lamps, infrared temperature sensors, assembling plates and driving devices; the cigarette clamps are arranged on the fixing plate; the infrared temperature sensors, the highlight lamps and the light baffle covers are all arranged on the assembling plates; the highlight lamps can generate straight-line shadow edges on cigarettes along the light baffle covers; the infrared temperature sensors are used for detecting the temperatures of combusted cigarettes and used for controlling the straight-line cigarette sucking machine to terminate the sucking; the driving devices are used for driving the assembling plates to stretch forwards and withdraw backwards. By adopting the sucking termination device, the automatic control on the sucking termination is achieved, the structure is simple, the operation is convenient, tedious manual cotton line winding procedures are canceled, and the damage to the cigarettes is reduced as the sucking termination device is not in contact with the cigarettes in the working process.