The invention belongs to the field of spinning materials, and firstly provides a hydroscopic fine denier/superfine denier chinlon master batch which is prepared by adding a hydroscopic modifier, a metallic salt, an antioxidant and other auxiliary agents into nylon 6 chips in proportion to perform melt blending and extrusion, wherein the hydroscopic modifier is PVP; the hydroscopic fine denier/superfine denier chinlon master batch is mixed with the nylon 6 chips to perform melt spinning in proportion, and hydroscopic fine denier/superfine denier chinlon POY filaments are prepared by further performing cooling, oiling bunching and winding on the hydroscopic fine denier/superfine denier chinlon master batch and the nylon 6 chips. The hydroscopic fine denier/superfine denier chinlon POY filaments have the filament number of 0.4 to 0.88 dtex, the breaking strength of 3.3 to 3.8 cN/dtex, the elongation at break of 60 to 120 percent and the fiber hydroscopicity of 4 to 10 percent, so the blank of producing the hydroscopic fine denier/superfine denier chinlon POY filaments by adopting a conventional spinning method at home and abroad is filled up, and simultaneously the improvement on the hydroscopicity of the chinlon POY filaments provides a wider application space for the chinlon POY filaments.