A new solid solution system, Pb(Mg(1-x/2)Mn(x/2)W1/2)O-3, is formed by replacing Mg2+ with Mn2+ in the Pb(Mg1/2W1/2)O-3 complex perovskite. The solid solution remains in the orthorhombic Pmcn symmetry up to x = 0.1. It is observed that for such a chemical modification, the surface of the grain changes significantly. A stepped surface nanostructure appears in the Mn-substituted perovskite. Detailed surface morphology of the stepped patterns was revealed by atomic force microscopy (AFM), which determined that the interlayer step height varies from 2.3 to 8.3 nm. Analyse by XRD, SEM, EDX, and AFM suggest that the nature of the stepped surface structure may be the result of etching rather than spiral growth or two-dimensional nucleation as it was previously believed.