The invention discloses a liquid metal printer and a method for repairing a liquid metal printing product. The repairing method comprises the following steps: scanning a target pattern to obtain a line defect of a liquid metal line in the target pattern; determining a defect type of the line defect, and selecting a corresponding repair strategy according to the defect type to carry out liquid metal supplement or erasing on the line defect. The invention solves the quality problem of the printed circuit caused by different defects by adopting different repairing modes for different circuit defects in the liquid metal printed circuit. In addition, the repairing method provided by the invention can be added into an automatic process for preparing a printed circuit of a liquid metal printer, thereby ensuring the stability and reliability of the printed circuit formed by the liquid metal printer integrally.