For low-temperature R32 refrigerant the results of the analyses of the properties on the base of which the second virial coefficient have been calculated are discussed. The linear equation for thermal dependency of the coefficient is made by approximation of the data. The relative divergence between theoretical and empirical values of the coefficient are less than 2% as a rule, temperature range being from 200 to 463 K (equal to the reduced temperature range from 0,57 to 1,32). The obtained equation fits the experimental data better than the other equations for the second virial coefficient. It may be used in correction of the R 32 refrigerant equation of state and in generalizing the data on temperature dependencies for the second virial coefficients of methane and its fluoro products.