In order to clarify the curing characteristics of upper tobacco leaves from paddy–tobacco growing area in southern China, the characteristics of yellowing, browning, water loss, chlorophyll degradation and polyphenol oxidase(PPO) activity of different quality fresh upper leaves were studied by using dark chamber and electric–heated flue–curing barn. The results showed that: The yellowing index of 4 quality leaves, namely, normal tobacco leaves, “slow–yellowing” tobacco leaves, “fast–yellowing” tobacco leaves and “premature senescence and pale” tobacco leaves were 1.58, 1.53, 1.60, 1.58, separately; the browning index of 4 qualities were 0.18, 0.13, 0.17, 0.33, separately; the proportionality of water loss rate of 4 qualities were 0.45, 0.61, 0.43, 0.43, separately; the degradation amount of chlorophyll of 4 qualities were 90.73%, 85.33%, 92.48%, 95.42%, separately; the degradation rate of chlorophyll of 4 qualities were1.26%/h, 1.19%/h, 1.30%/h, 1.33%/h, separately; the average value of PPO activity of 4 qualities were 0.21, 0.15, 0.23, 0.45 U, separately; yellowing and water loss of normal tobacco leaves, “fast–yellowing” tobacco leaves and “premature senescence and pale” tobacco leaves were quickly and curing of these leaves was easy, “slow–yellowing” tobacco leaves yellowed slowly and water loss was hard to obtain, the easy curing potential for “slow–yellowing” was medium; browning of normal tobacco leaves, “slow–yellowing” tobacco leaves and “fast–yellowing” tobacco leaves were slowly, their PPO activity were low and the endurable curing potential were good; browning of “premature senescence and pale” tobacco leaves was easily, its PPO activity was high and the endurable curing potential was medium.