The present disclosure relates to a vector pair for screening TDP-43 (TAR DNA-binding protein 43 or TransActive Response DNA-binding protein 43) oligomer formation, a cell line transfected with the vector pair, and a method of monitoring TDP-43 oligomer formation using the cell line. More specifically, the vector pair includes: a first vector including a first TDP-43 gene and a first fluorescence protein gene; and a second vector including a second TDP-43 gene and a second fluorescence protein gene, wherein a protein expressed from the first fluorescence protein gene and a protein expressed from the second fluorescence protein gene bind to each other to display fluorescence, by association between a protein expressed from the first TDP-43 gene and a protein expressed from the second TDP-43 gene. The vector pair is effective in that it makes it possible to monitor TDP-43 oligomer formation in living cells.