Abstract: Dissolved organic matter ( DOM) in natural water has a significant impact on determination of OTC． Through solid phase extraction and LC-MS-MS， the study focused on the impact characteristics of DOM with different concentrations from different origins in the determination of OTC． The results indicated that DOM with different concentrations had different effect on the determination of OTC，and the recoveries of OTC with nature soil DOM were higher than the commercial DOM presence． When the same concentration of DOM presence，the recoveries of OTC in sandy soil DOM were nearly equivalent to the absence of DOM，and the OTC recoveries decreased by degrees with the presence of domestic commercial DOM，river sedimentary soil DOM，import commercial DOM． At the same time，the signal of OTC didn’t generate by the determination of LC-MS-MS when the same concentrations DOM in the presence of solution，and the results indicated that the relationship between DOM and OTC brought about the determination change． Besides，the study provided the scientific advice for the analyses and data correction of antibiotics pollutants．