The well-known problem of the correlations between eruptive processes in the chromosphere and corona and peculiarities of the magnetic field structure in solar active regions (ARs) on the photospheric level are discussed in this paper. We study the time variations in the first four moments of distribution (over the field) of four integral parameters of the magnetic field of an AR. We used Huairou (PR China) and Solar Orbit Heliospheric Observatory, Michelson–Doppler Interferometer (SOHO/MDI) measurements of longitudinal magnetic fields for ten ARs. We study the following integral parameters of an AR: total magnetic flux F a , tilting angle A n , complexity parameter H u and relative total magnetic flux imbalance O v . The distributions of these parameters show essential differences between quiet and flare productive ARs. One can observe specific differences in the distributions before and during flares. The four first distribution moments take into account these differences and so they can be good quantitative parameters of the current states of ARs relative to their flare productivity.