  The problem of stochastis in multiple electron-photon head-on collisions has
been considered in this paper. The kinetic equations for the distributions over
the electron energy and collisions number along with the equations for these
distributions moments have been obtained. The equations for the first moments
have been solved by the iteration method. It has been shown that the variance
of the energy distribution as a function of the mean number of collisions has a
maximum at some value of $\bar n$. It is seen from this analysis that multiple
scattering of electrons influences on the spectra both electrons and photons
even for the photon target of small thickness. The data of approximate
analytical calculations agree with the results of the Monte Carlo simulation.
