The invention relates to a low-melting-point metal wire for 3D printing. The low-melting-point metal wire is prepared from raw materials comprising the following contents of, by weight, 20-45% of Bi,25-40% of Sn, and the balance In complemented to 100%. The melting point of the metal wire is 75-100 DEG C, by adjusting the relative content of Bi, Sn and In, the hardness and the tensile strength ofthe metal wire can be effectively improved, the demands of circuit printing, three-dimensional metal structural part printing and functional structural part printing combined with plastic can be met,and the low-melting-point metal wire has wide application prospects and high commercial promotion value.