The invention provides a portable drawing T-square comprising a shell and a straight ruler portion. At least one storage cavity used for storing the straight ruler portion is arranged in the shell. The side wall of the shell of the storage cavity is provided with an opening. One end of the straight ruler portion extends into the storage cavity from the opening, and the end of the straight ruler portion is hinged to the cavity wall of the storage cavity. The straight ruler portion can be placed in a storage cavity of the shell. The defects that an original T-square is inconvenient to carry, prone to breakage and the like are avoided. The portable drawing T-square is small in structure volume, low in manufacturing cost and convenient to carry, and a student can conveniently carry the T-square to conduct drawing design work.