The present invention relates to a coumarin compound that is used for analysis of enzymatic activity and enzyme inhibitor screening. The compound has a structure formula as shown in the right; wherein, R<1> is an H atom, ester prepared from hydrogen of OH that is substituted by aliphatic carboxyl or aromatic carboxylic acid, or ether that is prepared from hydrogen of OH that is substituted by carboxyl of sterol, monosaccharide and polysaccharide; R <2>, R<3> and R<4> can be H, alkyl containing 1 to 18 carbon atoms, perfluorinated alkyl containing 1 to 18 carbon atoms, -CN,-Ar, miscellaneous aryl, carbonyl or carboxyl amide. The coumarin compound adopts Pechmann reaction or Knovenagel reaction to introduce halogen atoms in the sixth and eighth positions of a benzene ring, to prepare the di-halogenated 7-hydroxycoumarin compound. The coumarin compound can be used as a fluorescent probe for marking analysis in the biotechnological research, and has the characteristics of simple operation, high stability, high sensitivity, high selectivity, and so on. And the coumarin compound is mainly used for the analysis of enzymatic activity, the enzyme inhibitor screening, and the detection of cell activity.