The invention discloses a promoter 32M6A and application thereof. The promoter named 32M6A is a DNA (deoxyribonucleic acid) molecule as shown in 7-94 nucleotides at a 5' tail end of a sequence 1 in a sequence table. The invention further discloses a DNA molecule (fusion gene) which is sequentially comprises a DNA molecule and a reporter gene as shown in 7-94 nucleotides at the 5' tail end of the sequence 1 in the sequence table sequentially from upstream to downstream. The invention also discloses a recombinant plasmid containing the fusion gene. The invention further discloses a recombinant bacterium obtained by leading of the recombinant plasmid into a hoist bacterium. The invention also discloses application of the recombinant bacterium to detection of 2,4,6-trinitrotoluene and/or 2,6-dinitrotoluene and/or methylbenzene and/or 2,4-dinitrotoluene and/or 1,4-dinitrobenzene. A biosensor can be applied to detection and identification of positions of explosives such as landmines in wartime and postwar, and a new method is provided for TNT (trinitrotoluene) detection in soil and water environment.