The ratio of positron/electron fluxes originated in nuclear spallation reactions in the Earth's magnetosphere is considered. It is supposed that positrons as well as electrons are produced in the decay of charged pions (pi±<FONT FACE=Symbol>® m</FONT>± ->e±) born in nuclear collisions of trapped relativistic inner zone protons with the residual atmosphere. These positrons and electrons are captured in the magnetosphere and create positron and electron radiation belts of nuclear origin. The positron/electron trapped magnetospheric fluxes formed with this mechanism are simulated and the resulting computed e+/e- flux ratio ~ 4 appears in agreement with the recent observations. This ratio is significantly different from the ratio ~1 obtained from the primary cosmic ray source through the same mechanism.