This paper summarizes significant progresses of quantifying organic substituent effects in recent 20 years. The main content including: (1) The principle of electronegativity equalization was widely accepted, and used to calculate the intramolecular charge distribution and inductive effect of groups. A valence electrons equilization method was proposed to compute the molecular electronegativity on the basis of geometric mean method, harmonic mean method, and weighted mean method. This new calculation method further extended the application of the principle of electronegativity equalization. (2) A scale method was established for experimentally determining the electrophilic and nucleophilic ability of reagents, in which benzhydryliumions and quinone methides were taken as the reference compounds, and the research field was extended to the gas phase conditions, organometallic reaction and radicals system. Moreover, the nucleophilicity parameters N and electrophilicity parameters E for a series of reagents were obtained. The definition and quantitative expression of electrophilicity index ω and nucleophilicity index ω - were proposed theoretically, and the correlation between the parameters from experimental determination and the indexes from theoretical calculation was also deeply investigated. (3) The polarizability effect parameter was initially calculated by empirical method and further developed by quantum chemistry method. Recently, the polarizability effect index of alkyl (PEI) and groups (PEIX) were proposed by statistical method, and got wide applications in explaining and estimating gas-phase acidity and basicity, ionization energy, enthalpy of formation, bond energy, reaction rate, water solubility and chromatographic retention for organic compounds. (4) The excited-state substituent constant σCCex which was obtained directly from the UV absorption energy data of substituted benzenes, is different from the polar constants in molecular ground state and the radical spin-delocalization effects constants in molecular radical state. The proposed constant R s correlated well with the UV absorption energy of many kinds of organic compounds, such as 1,4-disubstituted benzenes, substituted stilbenes, and disubstituted N -benzylidenebenzenamine. (5) The presence of the steric shielding effect distinguished three traditional steric effects. The stereoselectivity index Ci was proposed to quantify the stereoselectivity in addition reaction of carbonyl with nucleophilic reagent. The shielding parameter R S′ was defined to quantitatively express the specific surface of the reaction center screened by a group. Further, the topological steric effect index (TSEI) of a group based on the relative specific volume of reaction center screened by the atoms of substituents was proposed. These parameters have good applications in estimating the intramolecular dihedral angles, stereoselectivity of reaction, enthalpies of formation of alkene and alkylbenzene, acidity of substitutedimidazolium ionic liquid, and the reaction rate of alkane and hydroxyl free radical. In addition, some suggestions and prospects for further studies on quantifying the organic substituent effects were presented in this paper.