Abstract: In order to investigate the functional mechanism of potassium salts on combustion and pyrolysis of tobacco, the influences of potassium citrate and potassium nitrate on the characteristics of combustion and pyrolysis of flue-cured tobacco were analyzed by synchronous thermal analyzer (STA), automated physisorption analyzer (APA), microscale combustion colorimeter (MCC) and real-time temperature-rising infrared spectrometer (RTR-IR). The results showed that:1) Both potassium citrate and potassium nitrate had dual effects on the combustion and pyrolysis of tobacco, which were the acceleration of the degradation of tobacco's biopolymers at low temperatures (230℃-360℃) and deceleration of the coke pyrolysis at high temperatures (370℃-550℃). 2) The addition of potassium salts reduced the total pore volume and specific surface area of the coke, thus improving the compactness of coke. 3) Potassium ion catalyzed the degradation of oxygen-containing organic functional groups (O-H, C-O and C=O), while retarded the degradation of oxygen-free organic functional groups (C-H bond, C=C bond and aromatic moieties). 4) The nitrate ion from potassium nitrate displayed an oxidation acceleration effect on the decomposition of C-H moiety in flue-cured tobacco.