The invention discloses a pure polyester spinning finisher, which comprises the following components: fatty acid polyglycol ester, sodium dodecyl sulfate, trimethylolpropane tricaprylate, kaolin, sepiolite, ethylhexyl palmitate, 2-mercaptobenzimidazole, polyethylene glycol octadecylene, triethanolamine oleate, dioctyl sebacate, sodium acetate, zinc oxide, N, N-dimethylaniline, diallyl phthalate, and potassium persulfate. By means of the specific components and the weight parts of the components, the pure polyester spinning finisher provided by the invention has improved coating performance to polyester fiber, and the coat rate is as high as 99.5%, the rate of waste silk caused by filament bifurcation and end breakage is reduced to 4.3%, bifurcation, end breakage and other damage situations occurring to the produced yarns is significantly reduced, the quality of the prepared pure polyester is improved, and the cost is reduced.