The optical absorption spectra(Qy band)are presented for Chlorophylls and their derivatives bearing formyl groups(CHO)or dicyanoethenyl group(CH=C(CN)2)at a variety of positions such as the sites along Y axis(R2,R3,R12 and R13)and the formyl group(CHO)or the amino group(NH2)along X axis(R7,R8)by TDDFT method.The impacts of the number and positions of these substituents on the characteristics(energies,electron distributions)of the frontier molecular orbitals as well as the spectral properties were discussed.NBO and NPA analysis were used to show the effect of the distribution of π electrons on the macrocycle on the spectral properties.The results indicate that the Chls derivatives with two strong electron-withdrawing and conjugated groups at non-ortho-positions along Y axis(R2 with R12/R13,R3 with R12/R13)show redshifed Qy bands and stronger oscillator strengths,especially the groups with strong electron-withdrawing and well conjugated at R13 and R2 can enhance the oscillator strength evidently,and the strong electron-releasing group at R7/R8 along X axis can increase the redshift of the Qy band.