This study has been conducted to give some ideas for reasonable ecological management of Taejon city and its adjacent forest ecosystem against the effect of acid rain. Rain monitoring points to analyse its components represented 1 point in industrial area, 4 points in commercial area. 4 points in residential area, and 5 points in suburban area and forest survey was done in 7 forest sites adjacent to rain monitoring points. Transformed vegetation index(TVI) based on Landsat TM data was analysed far forest area. Taejon area was seriously contaminated by air pollutants and average concentration of anions in precipitation were 20.16㎎/ℓ for SO₄^(2-). 3.65㎎/ℓ for NO₃^-, and 3.09㎎/ℓ for Cl^-. Anion in precipitation were 1.09㎎/㎡/month for SO₄^(2-). 0.23㎎/㎡/month for NO₃^-, and 0.20㎎/㎡/month for Cl^-. Cation in precipitation were 0.14㎎/㎡/month for Ca^(2+), 0.10㎎/㎡/month for NH₄^+, 0.08㎎/㎡/month for Na^+, 0.07㎎/㎡/month for K^+, and 0.08㎎/㎡/month for Mg^(2+). The region with the highest concentration of SO₄^(2-). NO₃^-, and Cl^- in rain was industrial area. SO₄^(2-), NO₃^-, and Cl^- concentrations in industrial area were 43.08, 3.88, and 3.64ppm, respectively. Forest soil showed strongly acidic ranging pH4.16-4.94. Transformed vegetation index (TVI) were 3.11 in Dangsan, 4.00 in Kyechoksan, 4.13 in Bomunsan, 4.18 in Kabhasan, 3.34 in Bongsan. 4.13 in Sikchangsan, and 4.20 in Seongchisan. Dangsan forest located near in industrial area showed the lowest TVI.