The acute toxic effects of mercury (Hg) and bromoxynil (BX) on Enchytraediae Fridericia bulbosa in OECD soil were investigated. The results suggested there was statistically significant differences (p<0.05) between negative controls and exposure experiments except the lowest concentration of single pollutant. The 14-d LC50 values for F. bulbosa exposed to Hg and BX were 0.73 and 0.48 mg kg-1, respectively. The concentration of BX significantly influenced to the mortality of earthworms by Hg，and BX was the main contributive factor of the combined toxic effects. The interactive effects between Hg and BX were synergistic when the concentrations of BX were 0.25 and 1 mg kg-1. While BX concentration was 4 mg kg-1, the interactive effects were antagonistic. It can be concluded that F. bulbosa is a suitable test species to measure the acute toxicity of HM and pesticide, and the morality may be considered as a valuable and sensitive biomarker diagnose adverse effects of Hg or BX in soil environment.