Abstract: In order to further optimize spinning technology and improve the quality of metachromatic flat polyester filament, three different specs of metachromatic flat polyester filaments were designed , and the structure and properties of metachromatic flat and flat polyester filaments were tested and analysed. The results showed that: The cross section of metachromatic flat polyester filament is nonuniform size and irregular rectangle, and the edges is the elliptic shape. The distribution of thick and thin is the main factor to influence yarn properties. The more thick part percentage is, the greater the yarn breaking elongation, moisture regain, boiling shrinkage and the dyeing-uptake have, and the smaller the breaking strength has. The dry heat shrinkage has less dependance on time and greater influence on temperature. Especially, the shrinkage rate of the metachromatic flat filament wes significantly increased with the increase of the temperature.

Key words: metachromatic flat polyester filament , pure flat polyester filament , structure and property , testing and analysis