The rare earth SmFe2 and CeFe2 Laves phases and solutions on base of them with partial substitution by terbium ((Sm,Tb)Fe2, (Ce,Tb)Fe2) were obtained. The lattice parameters of compounds were refined by Rietveld method. To study the effect of substitution on the magnitudes of magnetostriction and magnetization of alloys, measurements in the temperature range 78-360 K in magnetic fields up to 1.2 T were carried out. Using Belov-Arrot method, the Curie temperatures for series of compounds in Ce1-xTbxFe2 (x = 0; 0.1 and 0.2) system were determined. It was found that in the Sm1-xTbxFe2 system, a change in the sign of magnetostriction should be observed at x = 0.4 - 0.45, which correlates well with X-ray diffraction data.