The utility model provides a fine particles air duct of sampling for low temperature environment for flue gas dilution system and fine particles trap when connecting the sampling, wherein, sampling air duct (1) is multilayer cover tubular construction, and its inlayer is well air defence static elastic rubber hose (100), and the intermediate level is porous insulation material layer (200), outer be flexible waterproof fixed bed (300). The utility model provides a connect the fine particles sampling air duct that fine particles dilutes sampling system and particulate matter trap, it has anti condensation, prevent the structure of static, be applicable to low temperature sampling environment, and what the air duct of sampling adopted is the flexible coupling mode that has certain intensity, the ease for use and the suitability of sampling air duct have been ensured, easily connect, the gas tightness is good, can effectively prevent because fine particles pipeline loss that pipe wall dewfall and air current friction led to the fact, sampling accuracy and reliability have as a result been improved.