This paper studies the application of Meti-Lis model to determine the state and forecast to 2020 of air pollutants from TPS and SO2 in Thai Nguyen city to 2020 using different scenarios. Results have shown that Thai Nguyen city has been polluted by TPS in some areas, such as Phu Xa, Gia Sang Ward. At the some routes such as Cach Mang Thang Tam and Luong Ngoc Quyen street have had high concentration dust that exceeded the acceptable limits of Vietnam. The research results have revealed that current concentration of SO2 in almost areas is lower than the standards. The spread of air pollution to 2020 in scenario has indicated air environment in Thai Nguyen city will be serirously polluted by TSP and SO2. Scenario 2 has shown that air environment in some areas and main traffic junctions in Thai Nguyen city will remain polluted. According to scenario 3, the air environment in Thai Nguyen city will be at "safe" levels for the air surrounding and within the permissible limits.