Abstract: A field experiment was conducted to study the changes of polyphenol contents and enzyme relating to polyphenol synthesis and the relationship between them in three sun-cured tobacco varieties in Jilin. The results showed that the total phenols content Qinghuangye > Dayehuang > Dabaiihua in the three sun-cured tobacco varieties in Jilin, with range 0.16% to 1.2% in the whole growth period. The total phenols increased with increasing leaf age, and decreased slight in late mature. Chlorogenic acid, rutin and scopoletin showed an upward trend during leaf development in Qinghuangye and Dayehuang, but they showed a single peak curve in Dabaihua. Phenylalanine ammonia lyase (PAL) activity had the same trend with chlorogenic acid and rutin in all varieties. Polyphenol oxidase (PPO) activity and peroxidase (POD) activity showed a single peak trend. With the growth and development of tobacco leaves, phenylalanine ammonia lyase activity with chlorogenic acid, rutin, scopoletin changes and total phenols were positively correlated, and with chlorogenic acid and rutin was significantly correlated. Peroxidase activity with chlorogenic acid, rutin, scopoletin and total phenols were positively correlated, and with total phenol reached significant levels. There was significant correlation between phenylalanine ammonia lyase, peroxidase and polyphenol contents. We can regulate the activity of two enzymes to control content of polyphenols, then improving the quality of tobacco finally.