The invention provides a preparation method of an asymmetric 
hollow fiber membrane, which comprises the following steps: preparing a membrane 
casting solution, and extruding the membrane 
casting solution into a molded product through a die head, performing split-phase curing on the molded product, and performing 
quenching treatment to obtain a green film; then extracting a 
solvent system in the green film by using an extracting solution at the extraction temperature of 40-80 DEG C and the concentration of the extracting solution in the extraction process is not lower than 90%, so that the 
solvent system can be removed from the green film only by 1-4 hours; performing low-temperature 
drying and high-temperature shaping on the original membrane to obtain a 
hollow fiber membrane; according to the method, in the process of preparing the 
hollow fiber membrane, the extraction time can be shortened, and the extraction quality can be ensured, so that a 
solvent system can be completely removed from membrane filaments by the extract liquor within a relatively short time, and the economic benefit is ensured; meanwhile, it can be guaranteed that the finally prepared hollow 
fiber membrane has long 
plasma permeation time, and the 
plasma permeation time is at least 48 h; and the membrane also has high gas 
mass transfer rate and large mechanical properties, and is especially suitable for being used as a 
blood oxygenation membrane.