The utility model relates to a nitrogen trifluoride electrolysis trough sampling device belongs to the process gas sampling technology field. Nitrogen trifluoride electrolysis trough sampling device include the nitrogen trifluoride electrolysis trough, pretreatment column is connected at nitrogen trifluoride electrolysis trough top, pretreatment column connects the vacuum pump, the export of vacuum pump is passed through the air pocket valve and is connected sampling bag, connect the vacuum pump on the pipeline between nitrogen trifluoride electrolysis trough, the pretreatment column. The utility model discloses simple structure, easily operation, sample swiftly make things convenient for, displace through the gas to in the sampling bag for the representativeness of sample gas is strong, has reduced the error of manual operation, has improved work efficiency, and the pretreatment column of setting can effectively prevent pipe -line system's corruption and jam, and extension detecting instrument life reduces and detects the cost, reduces sample personnel's potential safety hazard simultaneously.