[Objective]The paper was compare the control effects of different doses of MCPA-Na on weeds in foxtail millet field.[Method]Different doses of MCPA-Na were sprayed on foxtail millet field,while artificial weeding and spraying water was designed as control. The strain control effect and fresh weight control effect were calculated. [Result]The strain control effect and fresh weight control effect of 2 250 g/hm~2 MCPA-Na at 25 and 40 d post spraying were the best,and the fresh weight control effects reached 84. 19% and 87. 23%,respectively. Compared to CK,the yield increase effect of 1 500 g/hm~2 was the best,and the yield increase rate was 54. 31%; followed by 1 125 g/hm~2. Generally,1 500 g/hm~2 was the best dosage of MCPA-Na in foxtail millet production. [Conclusion]The paper provided a theoretical basis for screening the best dose of herbicide in foxtail millet production. [Objective] The paper was compared to control effects of different doses of MCPA-Na on weeds in foxtail millet field. [Method] Different doses of MCPA-Na were sprayed on foxtail millet fields, while artificial weeding and spraying water was designed as control The strain control effect and fresh weight control effect were calculated. [Result] The strain control effect and fresh weight control effect of 2 250 g / hm ~ 2 MCPA-Na at 25 and 40 d post spraying were the best, and the fresh Compared to CK, the yield increase effect of 1 500 g / hm ~ 2 was the best, and the yield increase rate was 54. 31%; followed by 1 125 g / hm ~ 2. Generally, 1 500 g / hm ~ 2 was the best dosage of MCPA-Na in foxtail millet production. [Conclusion] The paper provided a theoretical basis for screening the best dose of herbicide in foxtail millet production.