The effects of radiative losses on premixed laminar methane/air flame propagation char-acteristics were simulated in this paper with the detailed chemistry and transport propertiesby using the simplified radiative model which derived by assuming that the flames of interestare opticalIy thin and adopting the grey-medium approximation. Case studied include leanlaminar methane/air flame speed and flame standoff distance relative to the burner surface.The model predictions are compared with experimental data, and agreement is generallyvery good. The results have shown that radiative heat 1oss from the combustion productsare probably the dominant process leading to flame extinction at microgravity. It is importantat the fundamefltal flammability limits. Meanwhile, the flame standoff distance calculationsare also presented in this paper. To include the radiative heat loss, the fiame clearly standoff from the burner surface. This longer flame stand off imp1ies a weaker heat feedback fromthe fiame which is the same as the behavior of the candle flame at microgravity.