Ab initio and chemical kinetic study of the hydrogen atom abstraction reactions by the hydrogen radical on ethyl formate,ethyl acetate,ethyl propanoate,ethyl butanoate have been performed.Geometry optimizations and frequency calculations of all of the species including the transition states have been performed with the B3LYP method by using the 6-311G(d,p)basis set.The intrinsic reaction coordinate(IRC)calculations are performed to verify that the transition states are the right minima connecting the reactants and the products.Electronic energies for all of the species are reported at the CCSD(T)/CBS(extrapolated from CCSD(T)/cc-pVXZ,in whichX= D,T,Q)level of theory with the zero-point energy corrections.High-pressure limit rate constants at temperatures from 300 to 2500 K have been calculated for all of the reaction channels using conventional transition state theory with asymmetric Eckart tunneling corrections,and the data are fitted to the modified three parameters Arrhenius expression using least-squares regression.This format of rate coefficients is compatible with the Chemkin software and can be directly used in detailed combustion chemical kinetic modeling.Further,a branching ratio analysis for each reaction site has also been investigated for all of the ethyl esters studied in this work.