Abstract: 218 samples of flue-cured tobacco leaves of representative area in China were collected to investigate relationship between major appearance characteristic and deliveries of harmful compounds in mainstream smoke of flue-cured tobacco leaves. Variance analysis was used to study the difference of deliveries of tar, nicotine and seven harmful ingredients (carbon monoxide, benzopyrene, phenol, hydrogen cyanide, NNK, ammonia, crotonaldehyde) in mainstream smoke between different characteristic of maturity, color, body, oil, leaf structure, color intensity of flue-cured tobacco leaves. Results showed that color, body, leaf structure of tobacco leaves had significant influence on deliveries of harmful compounds in mainstream smoke, but that of the maturity, oil and color intensity had a little influence .The deliveries of tar, nicotine, phenol, ammonia, hydrogen cyanide in mainstream smoke of orange tobacco leaves were greater than that of lemon tobacco leaves. In general, the deliveries of nicotine, phenol in mainstream smoke of fleshy tobacco leaves were larger than that of less thin tobacco leaves. With the tobacco leaves structure tending to be loose, The deliveries of tar, nicotine and phenol in mainstream smoke were significant decrease, and the deliveries of crotonaldehyde were significant increase.