The invention discloses a prestressing duct mud jacking plumpness detecting method, which comprises the following steps of respectively collecting infrared thermal image sequences of air, reinforced concrete, metal bellows, rubber bellows, mud jacking materials and steel strands after heat shock, and storing the sequences; fast heating the surface of a concrete component to be tested to the preset temperature; collecting the infrared thermal image sequence of the surface of the concrete component to be tested; processing the infrared thermal image sequence of the surface of the concrete component to be tested; comparing the processed infrared thermal image sequence of the surface of the concrete component to be tested with the stored infrared thermal image sequences. The invention also discloses a prestressing duct mud jacking plumpness detecting system. The prestressing duct mud jacking plumpness detecting method and system provided by the invention has the advantages that the operation is simple; the detection speed is high; the accuracy degree is high; the infrared thermal image comparative analysis is combined, so that the detection result is more intuitive; the observation and the analysis by inspectors are convenient; the work efficiency is improved.