The invention discloses an application of a quinaldine compound as an hCBS (human cystathionine beta-synthase) enzyme inhibitor, and particularly relates to the application of the compound quinaldine blue as the hCBS enzyme inhibitor. The small-molecular compound has the IC50 on an in-vitro hCBS enzyme-catalyzed reaction of 20 [mu]M, and can be used as a tool drug for study on an H2S signal channel and a lead compound for development of drugs for treating circulatory shock, stroke, Down syndrome, tumor and other diseases related with H2S.