PURPOSE: To provide a crimped yarn having a specific relative viscosity in 98% sulfuric acid, a specified corrected fineness, etc., by comprising a polyamide produced by copolymerizing hexamethylene diammonium adipate with hexamethylene diammonium terephthalate in specific amounts, respectively.

CONSTITUTION: A polyamide produced by copolymerizing 60-90wt.% of hexamethylene diammonium adipate with 40-10wt.% of hexamethylene diammonium terephthalate is melt-spun, drawn and subsequently crimped to provide a crimped yarn. The crimped yarn has a relative viscosity of 2.4-4.0 in 98% sulfuric acid, a corrected fineness of ≥500 denier, a single fiber fineness of 10-50 denier, an elastic extension of ≥10% after treated in boiling water, an elastic extension of ≥5% after treated under a constrained load of 5mg/d in boiling water, a shrinkage degree of ≤5% in boiling water, thereby a good boiling water shrinkage degree, heat resistant strength retention degree, uniform fineness, crimping potential and dyeing uniformity and is suitable as a raw yarn for carpets.