[Objectives] The paper was to study the effects of different herbicides on weed control, agronomic characters and grain quality of Coix lacryma-jobi L. [Methods] Six commonly used herbicides were selected for the trial, including atrazine SC, butachlor SC, monosulfuron WP, MCPA-starane EC, clopyralid AS and tribenuron-methyl WP. [Results] (i) Atrazine, butachlor and monosulfuron had no chemical injury to C. lacryma-jobi L., while clopyralid caused slight chemical injur)', (ii) The fresh weight control effects of atrazine, butachlor and monosulfuron on weeds increased first and then decreased. The initial control effect of MCPA-starane and clopyralid reached more than 90%; the control effect of monosulfuron increased gradually in the late stage, reaching 97% at 60 d post spraying, and the overall control effect was optimal. (iii) Compared with manual weeding, herbicides had no significant effect on plant height of C. lacryma-jobi L. However, compared with no weeding, other herbicides except tribenuron-methyl inhibited plant growth to a certain extent. Herbicides had different effects on main stem diameter, tiller number per plant and grain number per plant of C. lacryma-jobi L. (iv) Different herbicides had no significant effect on 100-grain weight, but had significant effect on yield, (v) Compared with manual weeding, atrazine, butachlor and clopyralid decreased the protein content of C. lacryma-jobi L., and the use of atrazine, butachlor, monosulfuron, MCPA-starane and tribenuron-methyl decreased the fat content of C. lacryma-jobi L.; butachlor and MCPA-starane decreased the glycerol trioleate content of C. lacryma-jobi L. Compared with no weeding, chemical herbicides had no significant effect on the protein content, while atrazine decreased the fat content, and butachlor and MCPA-starane decreased the glycerol trioleate content of C. lacryma-jobi L. [ Conclusions] The use of herbicides significantly increases crop yield compared with no weeding, but has an impact on agronomic characters and grain quality. [ABSTRACT FROM AUTHOR]