Abstract: This study investigates the interference effects of multiple gases, including CO, SO₂, NO, NO2, and CH₄, on electrochemical sensors in flue gas analyzers under coexisting conditions. Zero-interference and cross-interference experiments were conducted. Results demonstrated that CO positively interfered with the SO₂ sensor, while NO and NO₂ negatively interfered with the SO₂ sensor, with NO₂ causing the most significant interference. An increase of 100mg/m³ in NO₂ resulted in a 0.173% reduction in the SO₂ sensor reading. NO exhibited significant positive interference with the CO sensor, causing a 0.116% increase in sensor reading per 100mg/m³ increase in NO. Conversely, CH₄ negatively interfered with the CO sensor, with each 100mg/m³ increase in CH₄ leading to a 0.005% decrease in the CO sensor reading.