Abstract: The present disclosure relates to microbiology and molecular biology, and specifically to a Clostridium-specific probe, use of the probe for detecting Clostridium content in pit mud and a method of detecting the Clostridium microorganism in fermentation pit mud using the probe. In view of the problem in the prior art that a method of detecting the number of Clostridium using fluorescence in situ hybridization has not been found, the present invention provides a complementary nucleic acid probe (SEQ ID NO: 1, named CLZ) specific to a conserved end sequence of 16S rRNA of Clostridium. The CLZ probe can be used to specifically detect Clostridium in samples such as fermentation pit mud, thereby providing an accurate and rapid analytical approach to investigate the regularity of Clostridium in a Luzhou-flavor liquor fermentation pit varying with age.