Abstract: To control broadleaf weeds and grass weeds in flax field by spraying at one time, the authors carried out application test on 3 new types of broadleaf weeds herbicides including 40% MCPA- sodium and bromoxynil octanoate EC and 7 kinds of grass weeds herbicides including haloxyfop-P to control weeds in flax field by spraying on stems and leaves of flax seedling. The results showed that: 40% MCPA- sodium and bromoxynil octanoate EC 1500 mL/hm2 or 30% bromoxynil octanoate EC 1500 mL/hm2 mixed with 7 kinds of grass weeds herbicides including 108 g/L haloxyfop- P EC 1500 mL/hm2 had excellent control effects on broadleaf weeds in flax field, the plant and fresh weight control effects were between 94.17%-98.71%. 40% MCPA-sodium and bromoxynil octanoate EC 1500 mL/hm2 or 30% bromoxynil octanoate EC 1500 mL/hm2, 80% bromoxynil SP 600 g/hm2 mixed with 108 g/L haloxyfop-P EC 1500 mL//hm2 or 10% quizalofop-ethyl EC 900 mL/hm2, 50 g/L pinoxaden EC 1350 mL/hm2, 15% clodinafop-propargyl WP 750 g/hm2 had excellent control effects on grass weeds in flax field, the plant and fresh weight control effects were between 97.22%- 100%. Comprehensive evaluation from safety on flax, control effect, herbicides cost and yield effect, 40% MCPA-sodium and bromoxynil octanoate EC 1500 mL/hm2 or 30% bromoxynil octanoate EC 1500 mL/hm2 + 108 g/L haloxyfop-P EC 1500 mL/hm2 or 10% quizalofop-ethyl EC 900 mL/hm2 are the best combination for controlling broadleaf weeds and grass weeds in flax field by spraying on stems and leaves of flax at one time, which should be popularized and applied in flax production.