Abstract: An applied study on fast bio_retting of flax was undertaken,and the results indicated that when compared with the conventional warm water retting of flax,this technique was characterized by shorter retting cycle time,high yield,good quality,high efficiency and slight pollution with retting cycle time reduced by over 70%,the rate of line flax increased by 3～4 percentage points,the quality of the fiber improved greatly,and discharge of BOD5 and SS reduced by 33% and 89% respectively.When 1 ton of flax stalk was processed,direct profit of more than 270 yuan was obtained.Its economic,social and ecological benefits are obvious.