The present invention relates to a compound as represented by formula (I), which is a condensation product of a theanine derivative and a carboxylic acid coumarin derivative, compounds as represented by formula (II) and formula (III), both of which are intermediates of the condensation product, a method for preparing these compounds, a pharmaceutical composition comprising the compounds, and a use thereof in preparing a medicament for prevention and treatment of tumors, inflammation, cardiovascular diseases, immune deficiency diseases and the like.Wherein,(Ia)R═CH3R1═HR2═H(Ib)R═CH2CH3R1═HR2═H(Ic)R═CH2CH3R1═ClR2═H(Id)R═CH2CH3R1═BrR2═H(Ie)R═CH2CH3R1═FR2═H(If)R═CH2CH3R1═NO2R2═H(Ig)R═CH2CH3R1═ClR2═Cl(Ih)R═CH2CH3R1═BrR2═Br(Ii)R═CH2CH3R1═NH2R2═HWherein,(IIa)R═CH3(IIb)R═CH2CH3Wherein,(IIIc)R1═ClR2═H(IIId)R1═BrR2═H(IIIe)R1═FR2═H(IIIf)R1═NO2R2═H(IIIg)R1═ClR2═Cl(IIIh)R1═BrR2═Br
