  Using the theory of relativity in superstrong magnetic fields (SMFs) and
nuclear shell model, we carry out estimation for electron capture (EC) rates on
iron group nuclei in SMFs. The rates of change of electronic abundance (RCEA)
due to EC are also investigated in SMFs. It is concluded that the EC rates of
most iron group nuclides are increased greatly by SMFs and even exceeded by
nine orders of magnitude. On the other hand, RCEA is influenced greatly by SMFs
and even reduced by more than eight orders of magnitude in the EC reaction.We
also compare our results with those of Fuller et al.(FFN) and Aufderheide et
al.(AUFD) in the case with and without SMFs. The results show that our results
are in good agreement with AUFD's, but the rates of FFN's are about close to
one order of magnitude bigger than ours in the case without SMFs. On the
contrary, our calculated rates for most nuclides in SMFs are increased and even
exceeded as much as for nine and eight orders of magnitude of compared to FFN's
and AUFD's results, which is in the case without SMFs, respectively.
