Abstract: The rare earth ions (RE³⁺:Nd³⁺,Sm³⁺)were loaded into the HMS by the in situ incorporation technique in which RE(NO₃)₃ was used as RE³⁺ precursor.The EPR spectra of synthesised samples were beeline.The distribution of zero region split parameter arose from substituting silicon atomic with rare earth.The EPR spectra of RE-HMS(RE:Nd,Sm) calcined nanoscale samples showed one isotropic line centered at g_iso=2.187,2.163，with peak to peak line width of about 0.03 T and 0.03 T,respectively.The mesoporous solid size of RE-HMS (RE:Nd,Sm) was 31 nm in Nd-HMS and 21 nm in Sm-HMS.The pore size of mesoporous materials RE-HMS (RE:Nd,Sm) from adsorption isotherms was 2.27 nm,2.18 nm,respectively.