The constant-volume combustion vessel and CHEMKIN PRO software were employed to investigate the effect of component variation of natural gas on the laminar burning velocity and flame instability at the ambient temperature and pressure and stoichiometric ratio. The results show that the laminar burning velocity of natural gas rises with the increase of ethane content

propane content and n-butane content

and the effect of the variation of ethane content on the laminar burning velocity is the most obvious. The instabilities of natural gas-air flames are decreased with the increase of ethane content

propane content and n-butane content. For inhibiting the overall instabilities of natural gas-air flames

the ability of n-butane is approximately equal to the ability of propane

both of which are greater than that of ethane. The flame structure analysis shows that the variation of the peak value of mole fraction of the radical H is the most significant when the natural gas composition fluctuates. There is a strong correlation between the laminar burning velocity of natural gas and the maximum values of the sum of mole fractions of OH and H. The sensitivity analysis of the laminar burning velocity and the net reaction rate analysis show that the natural gas component variation affects the important elementary reactions. The competition between the elementary reactions with positive impacts and the ones with negative impacts varies the peak of H mole fraction and the variation of ethane content has the greatest effect on the mole fraction of H.