The invention discloses a liquid metal rectangular pulse signal generator comprising a pipeline, conductive solution, liquid metal, an output terminal and a drive unit. The pipeline is formed into a closed space for storing the conductive solution; the liquid metal is in the conductive solution; the output terminal comprises a first terminal and a second terminal, one end of the first terminal andone end of the second terminal are inserted into the pipeline, and the other end of the first terminal and the other end of the second terminal are used for outputting rectangular pulse signals; andthe drive unit is used for controlling the liquid metal to move in the pipeline. Meanwhile, flowing continuity of the liquid metal is ensured by using an automatic time switch and a switching unit. The liquid metal rectangular pulse signal generator provided by the invention is simple in structure, has fewer elements, reduces a heating value during a working process, and avoids waveform distortion.