The effect of the starting powders, prepared by different heat treatment processes on the grain-oriented YBCO bulk materials, were studied by X-ray diffraction, scanning electron microscopy and a quantum design SQUID magnetometer. Results suggest that the specimens, which were calcined at 750-degrees-C for 10 h, heated at 950-degrees-C for 24 h, and then sintered at 930-degrees-C for 20 h, were preferentially c-axis oriented. The grain-orientation was found to be due to the partial melting of the YBCO compound.