  We estimate in this paper the errors in the zenith angle distribution for the
charged current events of the solar neutrinos caused by the uncertainty of the
earth electron density. In the model of PREM with a 5% uncertainty in the earth
electron density we numerically calculate the corrections to the correlation
between $ [N]_5 /[N]_2 $ and $ [N]_2 /[N]_3 $, and find the errors notable.
