Bulk YBa2Cu3Ox was prepared by a polymer chelate precursor method using poly[(N,N-dicarboxymethyl)allylamine] as a chelating polymer of which molecular weights were 3 x 10(4) (PDAA-L) and 3 x 10(5) (PDAA-H), respectively. X-ray diffraction (XRD) analysis of the precursor from PDAA-H shows that YBa2Cu3Ox (Y123) phase appeared after being calcined at 750 degrees C for 5 h and the mixture was completely converted to tetragonal Y123 phase after being calcined at 800 degrees C for 5 h. The phase evolution of the precursor from PDAA-H during isothermal experiment at 800 degrees C showed that pure tetragonal Y123 was produced even after the polymer chelate precursor was heated for 2 h in air, although a very small amount of BaCO3 was recognized. This BaCO3 phase was hardly recognized after 4 h calcination. The precursor prepared from PDAA-L was fully converted to pure tetragonal Y123 after 3 h calcining at 800 degrees C. On the other hand, the sample prepared from metal nitrate solution without PDAA was not fully transferred to Y123 phase after heating at 800 degrees C for 10 h. Large amounts of Y2O3, BaCO3 and CuO were observed. These results indicated that the greater homogeneity in the polymer chelate precursor leads to reduced firing times and temperature compared with the metal nitrate precursor.