Abstract: In order to get a clear idea about the difference between the traditional and siro polyamide filament core?-spun yarns and to organize effective production,researchers modified the existing spinning frame,produced the traditional and siro polyamide filament core-spun yarns,and tested the properties of the yarns.A comparison was made of the two kinds of core-spun yarn in terms of the spinning frame,yarn quality and spinning technology.It indicates that the traditional core-spun yarn can be manufactured on a spinning frame with additional feeder for core filaments and pre-drawing mechanism,while siro core-spun yarn can be made on a spinning frame which is fixed with siro spinning mechanism and core-spun unit.The quality of siro core-spun yarn is obviously better than that of the traditional one,especially in the core coverage,hairiness and evenness.They have similar rove drawing multiples,core yarn pre-drawing multiples,and roller gauges and pressure in processing.But the feed gauge between two roves of siro core-spun yarn should be smaller,and the twist factor of siro core-spun yarn is less than that of the traditional,but its spindle speed can be a little faster.