Effects of alternative magnetic field on phase structure in ceramic layer of ceramic lined compound steel pipes fabricated by SHS were described,and NiO was added as additive to contrast. The results show that change of phase structure in ceramic layer can not be observed in alternative magnetic field. With increasing in magnetic flux intensity,size of α-Al2O3 is decreased,and morphology is gradually transformed into fine equiaxed grain structure. Effects of alternative magnetic field are strengthened by adding NiO,which results in the refinement of grain size at a lower magnetic flux density.