Abstract: A novel fiber- or film-forming high-molecular-weight aromatic copolyamide consisting essentially of (1-A) a diamine recurring unit of the formula ##STR1## such as 3,4'-diaminodiphenyl ether or 3,4'-diaminodiphenyl sulfone, (1-B) a diamine recurring unit of the formula --HN--Ar.sub.1 --NH-- such as p-phenylene diamine, and (2) a dicarboxylic acid recurring unit of the formula --OC--Ar.sub.2 --CO-- such as terephthaloyl dichloride, wherein Y.sub.1, Ar.sub.1 and Ar.sub.2 are as defined in the specification, the total amount of recurring units (1-A) and (1-B) being substantially equimolar to recurring unit (2), and the proportion of recurring unit (1-A) being 7.5 to 40 mole% of the entire recurring units. The copolyamide is well soluble in solvents to give solutions having good flowability and stability that can afford shaped articles with superior thermal stability, fire retardancy and mechanical properties. A process for preparing the copolymer, and a dope of the copolymer are also provided.