Bacteria are one of the most common human pathogens, which not only seriously jeopardize human health and public health safety, but also bring about huge medical expenditures. Rapid and accurate bacterial detection is important for the treatment of bacterial infections. The spectral detection method can not only obtain the classification, content and functional status of bacteria promptly and in real time, but also has the advantages of simple operation and non-invasive, and has great potential in the field of bacterial detection. This paper describes the research and application of Raman spectroscopy, terahertz spectroscopy, visible and near-infrared light spectroscopy, fluorescence spectroscopy in bacterial detection, and the molecular mechanism of visible and near-infrared light spectroscopy, light targets, including bacterial retinal plasmids containing retinal chromophores, bacteriophytochromes with tetrapyrrole chromophores, photoactive proteins with p-coumarate chromophores, photo-oxidative stress structural domains with flavin-like mononucleotide chromophores, cryptochromes with flavin-adenine di-nucleotide chromophores. And blue-light sensing domains with flavin-adenine dinucleotides are described. Finally, optimization strategies for bacterial detection techniques are proposed with respect to the advantages and disadvantages of existing bacterial spectral detection techniques, hoping to provide help for the research of bacterial spectral detection.