The present work is to study effects of neutron irradiation on the structure of amorphous Pd80Si20 and Pd77.5Cu6Si16.5 alloys by using X-ray diffraction techniques, differential scanning calorimertry (DSC) and internal friction measurements. The irradiation appeared to produce obvious changes in the pair correlation function g(r) and radial distribution function RDF (r). The increases of crystallization temperature (Tx) and enthalpies of two specimens were found by DSC measurements after irradiation. The results of internal friction measurement show that the internal friction of the irradiated Pd80Si20 alloy is higher than that of the unirradiated in the temperature range of Tp. The structure changes before and after neutron irradiation are discussed in terms of the concepts of density fluctuation defects (p) and shear stress fluctuation defects (τ).