Thermospheric O/N2 can be retrieved from the radiance of OI 130.4 nm dayglow.In the paper,the algebraic relationship between the two variables is established,and the characteristics of the radiance varying with observing angle and solar zenith angles are discussed,based on which the look-up tables of the regularization factors are made up,thus putting up a method for retrieving thermospheric O/N2 from measurements of OI 130.4 nm dayglow and meanwhile introducing a correcting coefficient in the algorithm to dismiss the error brought about by the difference between the ideal atmosphere representative by NRLMSISE-00 and the real atmosphere.Finally,the simulated dayglow radiance data of Oct 1,2002 are used as an example to testify the validation of the algorithm.The results demonstrated that the algorithm is able to reconstruct most of the features of O/N2 and has an obvious advantage over the conventional algorithm.