Ge_xSi_1-x_/Si strained-layer superlattices were grown on Si(100) substrates under different temperatures by molecular beam epitaxy. Methods such as reflection high energy electron diffraction, X-ray double crystal diffraction, Rutherford back scattering, transmission electron microscopy and Raman scattering have been applied to study the growth and characteristics of the Ge_xSi_1-x_/Si superlattices. The result show that the optimum growth temperature are different for superlattices with different composition, the small the x the higher the growth temperature, and vice versa. For x=0.1-0.6, the Ge_xSi_1-x_/Si superlattices with flat interfaces, good crystal perfection and uniform periodicity can be obtained with growth temperature in the range of 400一600℃.