Abstract: The PET/PTT filaments will have different crimp properties under different time and with different media at the same temperature.The crimp shrinking rate of the PET/PTT filament will be 80%-90% of the total crimp shrinking rate in the first five minutes when treated at different temperatures,then will reach a balance shrinking rate.The higher the temperature is,the shorter the time reaches balance.The water will accelerate the moving of the macromolecules and the crimp appearance.In relaxation and under low load,the promotion effect to the macromolecules activity from water is higher than from the low load,the filament orientation decreases and the crimp appearances.The crimp shrinking rate and crimp elongation rate of PET/PTT filaments treated in boiling water are 10.2% and 131.9% higher respectively than those treated in the oven at 100℃.