Abstract: A method based on simulations of perfectly stirred reactor(PSR) and improved application mode of connectivity method and principal component analysis of the rate sensitivity matrix was adopted to reduce the detailed reaction mechanism of aviation fuel(surrogate fuel).The detailed mechanism containing 1020 irreversible reactions of 131 species was assembled using the combustion mechanism of surrogate fuel(80% decane and 20% 1,2,4-trimethylbenzene by weight) and the NO_X formation mechanism.The aim was to accurately reproduce the temperature and concentrations of important species(CO,CO₂,and NO) with less than 5% error at the condition of inlet temperature 800K,pressure 101325Pa,residence time 3ms,without heat loss and constant reactor volume in an adiabatic PSR.The results showed that the reduced mechanism met the desired target over a wide range of equivalence ratio(0.5～2.0).