The magnetic structure and anomalous behavior of the temperature dependence of magnetization at low temperatures for amorphous NdxT1-x(T=Fe, Co, Ni) thin films are discussed. It has been observed that the sudden drop of magnetization is at about 20 K, and the temperature corresponding to the sudden drop on the magnetization curves does not change with composition, we suggested that as the neodymium component exceeded a certain amount, in the ground state the asperomagnetic and the speromagnetie structures may coexist for these amorphous alloys. The sudden drop of magnetization at about 20K may be explained by the phase transition between the speromagne-tism and paramagnetism. The critical composition of neodymium component for eoexi-stance of these magnetic structures approximately corresponds to x≥0.45, 0.20 and 0.08 for Nd-Fe, Nd-Co and Nd-Ni amorphous thin films, respectively.