We discuss lithium abundance and 6Li/7Li isotopic ratio in atmospheres of some magnetic roAp stars. Overabundances of the lithium were found in atmospheres of some roAp stars based on the analysis of both lithium lines at 6104 Å and 6708 Å as well as the high values of the 6Li/7Li isotopic ratio (0.2 - 0.5). These facts can be explained by lithium production in spallation reactions on stellar surface and by preserving 7Li and 6Li isotopes to be destroyed in the inner layers of stellar atmospheres by strong magnetic fields near magnetic poles. Our synthetic spectrum calculations take into account magnetic line broadening effects.