Small angle X-ray scattering technique was used to investigate the evolution of microstructure in Cu60Zr30Ti10 amorphous alloy heated at temperatures from 300 to 813 K. It is confirmed that the Cu-rich domains in the diameter range about 30 nm exist in the as-quenched state. The structural relaxation can be divided into the low temperature structure relaxation in the temperature range from 300 to 573 K and the high temperature structure relaxation in the temperature range from 573 K to the temperature of glass transition. The Cu-rich domains with ordered clusters are the basis of crystallization. Porod curves indicate that there is a sharp boundary between the nano body-centred-cubic CuZr precipitates and the matrix.