The utility model discloses a boiler efficiency test flue gas sampler, including flue gas sampling pipe and sample case, the sample incasement is equipped with filter equipment, drying device and vacuum pump, flue gas sampling pipe one end is used for the directness and waits to take a sample the flue gas contact, and the other end is connected with filter equipment, filter equipment and drying device are connected, drying device and vacuum pump connection, be equipped with first stop valve between flue gas sampling pipe and the filter equipment, be equipped with the second stop valve between drying device and the vacuum pump. The utility model discloses boiler efficiency test flue gas sampler has effectively reduced the flue -gas temperature, has reduced smoke and dust content, has reduced flue gas humidity, prevents effectively that the flue gas is less than sour dew point, improves the flue gas pressure of sample pipeline, guarantees flue gas analyzer's normal work, and the trouble that reduces flue gas analyzer takes place.