The study on the effective permittivity of mixed solution is an important work to Microwave-Chemistry.Some new characteristics of effective permittivities of mixed solution have been found and can not be explained by the classic theory

such as Clausius-Mossotti’s

Onsager’s and Kirkwood’s formulas.The effective permittivity for biphase organic solution at microwave frequency has been obtained by the perturbation method.The results show that the real part (or the imaginary part) of the effective permittivity may has a peak value with respect to the fraction of volume.Where the effective permittivity is larger than any of that of the components while the real part of permittivity (or the imaginary part) of components is closed to each other and the imaginary part of permittivity (or the real part) is quite different.The analysis has been done to explain this new characteristics of effective permittivities by the symmetric Bruggrman's theory.