The invention discloses a chemical gas detection and identification method by hyperspectral imaging and relates to the chemical gas detection and identification method. By the chemical gas detection and identification method, the technical problems that on-site sampling is required and the detection speed is low in the conventional chemical gas detection and identification method based on a chemical method can be solved. The chemical gas detection and identification method comprises the following steps of: shooting a spectral image of a detected place when any chemical gas does not exist in the detected place so as to acquire a pixel vector of a background; acquiring a spectral vector of a detected chemical gas from a chemical gas spectrum library; shooting another spectral image of the detected place and filtering the second spectral image by using a filter; sequencing output values of the filter from large to small; setting a threshold of the chemical gas; inputting the output values of the filter and the threshold of the chemical gas into a judger; recording the output values, greater than the threshold, of the filter so as to acquire a chemical gas-containing pixel set; and judging pixels containing the chemical gas by using a minimum markov distance method so as to identify the type of the gas. The chemical gas detection and identification method can be used in the fieldsof detection for pollution gas emission of chemical factories and environment monitoring.