We investigated the neutrino energy loss by electron capture of the nuclide 56Fe, 56Co, 56Ni, 56Mn and 56Cr in superstrong magnetic field at the crusts of neutron stars. The results showed that the superstrong magnetic field has only a slight effect on the neutrino energy loss rates when B13 G on surfaces of most neutron stars. Whereas for some magnetars, the range of the magnetic field is 1013—1015 G, the neutrino energy loss rates would be lowered greatly and may be even decreased more than five orders of magnitude by superstrong magnetic field.