Abstract: A method for fiber splitting for conjugated fiber, which includes the steps of i) preparing polymers: charging a first polymer and a second polymer respectively into corresponding extruders and adding a nucleated agent, releasing agent or catalyst into one of the first and second polymers to differentiate crystallinity between the first and the second polymers, or differentiate crystallinity by adjusting viscosities thereof at different temperatures; ii) spinning: the first and second polymers are transferred to a spinning zone and are spun at a winding speed of 3000 to 8000 meters per minute to be conjugated fiber via a spin pack; iii) weaving; and iv) dyeing finishing, and the conjugated fiber is split during the dyeing and finishing step without any physical and chemical treatments.