A system for pneumatically lifting fuel elements of pebble-bed reactor group by group, comprising: a feeder having one outlet and at least two inlets; at least two burnup detection assemblies, each of the burnup detection assembly comprising one burnup detector and one buffer pipeline having a first end connected to an outlet of the one burnup detector and a second end connected to one of at least two inlets of the feeder, an amount of the inlets of the feeder being identical with that of the burnup detection assemblies; a gas power supply comprising a high pressure chamber and a low pressure chamber; a tee joint disposed at the outlet of the feeder and having two inlets connected to the outlet of the feeder and the high pressure chamber respectively and an outlet; a lifting pipeline having an inlet connected to the outlet of the tee joint and an outlet higher than the inlet of the lifting pipeline, a ratio D2/D1 of a diameter D2 of each fuel element to an inner diameter D1 of the lifting pipeline being in a range of 0.50-0.99; a gas diverter disposed at the outlet of the lifting pipeline and having an inlet connected to the outlet of the lifting pipeline, an outlet and a gas discharge port connected to the low pressure chamber; and a reactor feeding pipeline having an inlet connected to the outlet of the gas diverter, characterized in that the feeder comprises: a case having at least two feeding pipes connected correspondingly to the buffer pipelines of the burnup detection assemblies and a discharging pipe, central axes of the discharge pipe and the feeding pipes being at an angle of at least 5° with a horizontal plane; a rotating shaft; a rotating disc fixed onto the rotating shaft and formed with at least one fuel element discharging groove in a periphery thereof, central axes of the feeding pipes, the discharging pipe and the fuel element discharging groove being located in the same plane perpendicular to a central axis of the rotating shaft; and a driving device fixed onto the case and connected to the rotating shaft to drive the rotating shaft to rotate, wherein the feeder is configured such that the at least two fuel elements form a fuel element queue within the lifting pipeline. a feeder having one outlet and at least two inlets; at least two burnup detection assemblies, each of the burnup detection assembly comprising one burnup detector and one buffer pipeline having a first end connected to an outlet of the one burnup detector and a second end connected to one of at least two inlets of the feeder, an amount of the inlets of the feeder being identical with that of the burnup detection assemblies; a gas power supply comprising a high pressure chamber and a low pressure chamber; a tee joint disposed at the outlet of the feeder and having two inlets connected to the outlet of the feeder and the high pressure chamber respectively and an outlet; a lifting pipeline having an inlet connected to the outlet of the tee joint and an outlet higher than the inlet of the lifting pipeline, a ratio D2/D1 of a diameter D2 of each fuel element to an inner diameter D1 of the lifting pipeline being in a range of 0.50-0.99; a gas diverter disposed at the outlet of the lifting pipeline and having an inlet connected to the outlet of the lifting pipeline, an outlet and a gas discharge port connected to the low pressure chamber; and a reactor feeding pipeline having an inlet connected to the outlet of the gas diverter, characterized in that the feeder comprises: a case having at least two feeding pipes connected correspondingly to the buffer pipelines of the burnup detection assemblies and a discharging pipe, central axes of the discharge pipe and the feeding pipes being at an angle of at least 5° with a horizontal plane; a rotating shaft; a rotating disc fixed onto the rotating shaft and formed with at least one fuel element discharging groove in a periphery thereof, central axes of the feeding pipes, the discharging pipe and the fuel element discharging groove being located in the same plane perpendicular to a central axis of the rotating shaft; and a driving device fixed onto the case and connected to the rotating shaft to drive the rotating shaft to rotate, wherein the feeder is configured such that the at least two fuel elements form a fuel element queue within the lifting pipeline. a case having at least two feeding pipes connected correspondingly to the buffer pipelines of the burnup detection assemblies and a discharging pipe, central axes of the discharge pipe and the feeding pipes being at an angle of at least 5° with a horizontal plane; a rotating shaft; a rotating disc fixed onto the rotating shaft and formed with at least one fuel element discharging groove in a periphery thereof, central axes of the feeding pipes, the discharging pipe and the fuel element discharging groove being located in the same plane perpendicular to a central axis of the rotating shaft; and a driving device fixed onto the case and connected to the rotating shaft to drive the rotating shaft to rotate, wherein the feeder is configured such that the at least two fuel elements form a fuel element queue within the lifting pipeline.