The invention belongs to the technical field of textile assistants and discloses a scouring agent for short-process pretreatment. The scouring agent contains the following components in parts by weight: 12-20 parts of sodium dodecyl benzene sulfonate, 1-4 parts of nonyl phenol, 0.9-10 parts of isoflurane, 1-1.5 parts of pethidine, 5-7 parts of acrylate, 10-15 parts of acrylonitrile, 12-14 parts of polymethylhydrosiloxane, 1-12 parts of diethylpropanediol and 90-150 parts of ethanol. The invention also discloses a method for preparing the scouring agent, application of the scouring agent in a desizing/scouring one-step process of cotton-polyester blended fabrics, in a desizing/scouring-bleaching two-step process of pure cotton fabrics and a cold pad-batch process of cotton-polyester blended fabrics, and further discloses a technological process of the process and a padding liquid formula. The scouring agent disclosed by the invention is rapid in penetration, high in emulsifying capacity, high in detergent washing capacity, high-temperature-resistant, oxidant-resistant, wide in application range and good in treatment effect.