The invention relates to a method for producing n-alkane solvent oil from Fischer-Tropsch synthetic oil. According to the method, low-temperature Fischer-Tropsch synthetic light oil is adopted as a raw material, and is processed through upgrading and distillation separation processes with a fractionation tower, hydro-finishing, a degassing tower, a C6/C7 cutting tower, a C5/C6 cut tower, a C10/C11 cutting tower, a C8/C9 cutting tower, a C7/C8 cutting tower, a C9/C10 cutting tower, a C13/C14 cutting tower, and a C17/C18 cutting tower; such that various types of solvent oils such as n-pentane-rich, #6, #120, #140, #200, #D30, #D40, #D65, #D100 and #D120 solvent oils can be obtained. Compared to prior arts, all products produced with the method are n-alkane solvent oils. The method has the advantages of simple process flow, more produced solvent oil types, high solvent oil quality, and the like.