There is provided a method for a purification of trichlorosilane, the method including: performing a pretreatment for separating a chlorosilane mixture from reaction products of a trichlorosilane production reaction; performing a first purification for separating the chlorosilane mixture into a first top stream and a first bottom stream; performing a second purification for separating the first top stream into a second top stream and a second bottom stream; and performing a third purification for separating the second bottom stream into a third top stream and a third bottom stream, wherein the performing of the third purification is carried out under pressure conditions higher than those of the performing of the second purification, and a heat exchange is generated between the second bottom stream and the third top stream.