Nanosized Gd2CuO4 cuprate oxide was prepared at a low temperature using an amorphous heteronuclear complex, Gd2Cu(DTPA)(1.6). 6H(2)O, as a precursor. DTA and TGA indicated that the precursor can be completely decomposed above 500 degrees C. XPS indicated the decomposition product consisted of Gd2CuO4 cuprate oxide after the precursor was calcined at 500 degrees C for 2 h. XRD demonstrated that the nanosized crystalline Gd2CuO4 cuprate was formed after the calcination temperature increased to 600 degrees C. TEM showed that the particle size of Gd2CuO4 cuprate increased from 20 to 50 nm when the calcination temperature increased from 500 to 800 degrees C, and the particle size increased from 10 to 30 nm when the precursor was calcined at 500 degrees C from 1 to 8 h.