The invention discloses a manufacturing method for a polyolefin fiber for adsorbing an organic liquid, which comprises the following steps: 1) adding 500-2000ml polymeric monomers, initiating agents accounting for 0.5-0.8% of the total mass of the polymeric monomers, 1500-6000ml deionized water and dispersing agents accounting for 0.5-1% of the total mass of the deionized water into a polymeric kettle, fully stirring till forming a homogeneous phase solution, and then introducing nitrogen, heating up to 80-85 DEG C and reacting for 2-5 hours, and then heating up to 90-95 DEG C and continuing reacting for 1-2 hours, thereby obtaining a reaction product; washing, drying and crushing the reaction product, thereby obtaining a white powdered copolymer; 2) drying the obtained copolymer, mixing the copolymer with polyolefin granular materials according to the mass fraction of (10-50):(90-50), and then extruding from a double-screw machine and pelletizing, wherein the polyolefin granular materials are fibrous polypropylene or polyethylene granular materials with a spinning temperature of 140-250 DEG C; and 3) melting and spinning the granular materials by using the double-screw machine, thereby obtaining the polyolefin fiber.