Various antimicrobial agents are widely used for the purpose of antimicrobial process. We investigated anlimicrobial activity and reduction efficiency of mal-ordour by the diphenyl ether compound (2,4,4` - trichloro - 2` - hydroxy diphenyl ether) against Staphylococcus aureus(S.aureus) and Proteus vulgaris(P.vulgaris) causing the mal-ordour. Especially, the diphenyl ether compound is not restricted to the regulation of water-contamination. In this research, we found that the optimum concentration of diphenyl ether compound was 1.5w% for both strains and antimicrobial expressions were c^0.38t = 2.56 for S.aureus, c^0.38t = 2.67 for P.vulgaris. We found also that -OH group played the role of antimicrobial functional group. Lastly, reduction effect of mal-ordour was more than 90% for both strain at the optimum conditions.