Production method of acrylic yarn manufacturer: polyacrylonitrile fiber requires high purity of raw acrylonitrile, and the total content of various impurities should be less than 0.005%. The second monomer polymerized is mainly methyl acrylate, which can also be used to improve the spinnability and the hand feel, softness and elasticity of the fiber; The third monomer is mainly to improve the dyeability of fibers, generally itaconic acid containing weak acid dyeing group, sodium propene sulfonate containing strong acid dyeing group, sodium methacrylate sulfonate, sodium p-methacrylamide benzene sulfonate, methyl vinyl pyridine containing basic dyeing group, etc.