Abstract:Effect of malic urea crystal fertilizer(CF) on the contents of free amino acids, total sugar, nicotine and the qualities of raw tobacco leaves was studied. The results of 2yr experiments showed that contents of acid amino acid, alkaline amino acid except ARG, and most of neutral amino acid increased with the levels of CF. The contents of MET, ORN, TRP were lower than that of no fertilizer and equal N of compound fertilizer treatments, and the contents of G ABA, TAU, LEU, VAL were reduced as the levels of CF increased, but the contents of ARG, CYS, ILF were very low in all of treatments. Application of CF with equal N, the contents of potassium, total sugar and reduced sugar increased 15.6%～19.5%,13.3%～17.7%, and 10.5%, and the contents of tar in cigarette smoke and chlorine in raw tobacco leaves reduced by 16.9 % and 37.5%, respectively as compared with treatment of compound fertilizer. CF supplied to tobacco, the ratio of sugar to nicotine in the raw tobacco leaves was more suitable than that two control treatments. The qualities, amount and density of fragrant smoke of raw tobacco leaves enhanced 2 grades, 1 class and 1 class than compound fertilizer treatment. It is suggested, the quality of raw tobacco leaves was noticeably improved by supply of the crystal fertilizer.