An experiment was done to test how well a wet desulphurization device removes SO2 from flue gas using ammonia. Factors like pH, absorption concentration, and gas temperature were studied. Results showed that desulphurization rate increases with absorption concentration and pH, but decreases with SO2 concentration. Gas temperature doesn't affect desulphurization much. The best parameters for high desulphurization rate were found to be a liquid-gas ratio of 2.4 to 2.8 and a pH value of 5.8 to 6.5 when the SO2 concentration is 2,500 mg/m3. With these parameters, a desulphurization rate of 95% can be achieved. This experiment can help industries improve their desulphurization processes.