Based on a study of mineral paragenetic relationship in combination with results obtained by previous researchers, the authors divided the metallogenic process of the Wulaga gold deposit into three ore-forming stages and figured out the ore-forming thermodynamic parameters of each stage according to thermodynamic data. The first stage was the pyrite-early white chalcedony-like quartz stage, during which Eh values varied in the range of -0.5～+0.3 V, implying a weak reduction environment, and sulfur fugacity should be higher than 10^-23; the second stage was the ash-gray chalcedony-like quartz- polymetallic sulfide stage, during which the ore-forming environment at low temperature was an intermediate-acid (pH=4) weakly reducing environment, the sulfur fugacity should be higher than 10^-40 but not in excess of 10⁰, and the lower limit of the sulfur fugacity decreased as compared with that of the first stage; the third stage was the carbonate-quartz stage, during which the formation of the carbonate minerals foreboded the ending of the mineralization, the pH values of the metallogenic media changed gradually from acid (pH=3) to intermediate-acid (pH=5), ore-forming Eh values also showed transition from weak reduction (-0.5 V) to weak oxidation (+0.3 V), the lower limit of the sulfur fugacity varied around 10^-23 and was not in excess of 10⁰, and the oxygen fugacity varied around 10^-20. The data obtained by the authors are of important reference value for the in-depth investigation of the hydrothermal ore-forming process.