PURPOSE: An aromatic polyamide copolymer that has a combination of specific structure units, thus being high soluble in an organic solvent is employed to produce title fibers with a strength of over about 16g/de, a Young modulus of over about 300g/de and high fatigue resistance.

CONSTITUTION: An aromatic copolyamide that comprises structure unit A of formula I, unit B of formula II, and unit C of formula III and has MA, MC, mole% of units A and C respectively, satisfying 10 ≤ MA ≤ 80 and 20 ≤ MC ≤ 45 respectively and an intrincic viscosity of over 2.5 is em ployed. The copolyamide is dissolved in dimethyl acetamide or N-methylpyrrolidone or their mixture, which may contain inorganic salts and spun by a wet or dry method. The resulting yarns are drawn at a ratio of at least 3.5.

EFFECT: The copolyamide is high soluble in an organic solvent and the dope can be readily spun and drawn.