The utility model discloses a be used for hot sampling tube of boiler near -zero release measuring companion, including the sampling tube, the sampling tube be divided into bend loss and straight tube section, the cladding has the one deck zone of heating in the straight tube section of sampling tube, in the straight tube section of sampling tube still the cover have a sleeve pipe that is used for encapsulating the zone of heating. The zone of heating on still be provided with temperature sensor. The outer cladding of zone of heating have an one deck heat preservation, the heat preservation is also including the quilt cover tube package. Heat preservation and cover gapped between the inside pipe wall. Detachable the installation in the straight tube section of sampling tube of sleeve pipe, the sheathed tube both ends are provided with the end cover. The utility model discloses a device all is suitable for industry pulverized coal boiler, gas boiler and coal -fired power plant boiler as boiler near -zero release measuring device. Device simple structure, easy to carry out, can effectively guarantee advantage such as boiler near -zero release measuring authenticity.