In this paper, the stochastic magnetic field lines diffusion is studied. The
stochastic behavior of the magnetic field
lines is described by the generalized mapping to the second order which is derived
from the magnetic field lines
equations. The diffusion coefficient is calculated analytically using the Fourier
paths technique and the characteristic
function formalism. Both, they give exactly the same result of the diffusion
coefficient. A numerical determination of
the diffusion coefficient is also done.