The crystallization metastable zone width and induction period of L-tartaric acid in water were measured by laser method at the temperature range of 20-60℃. The influences of saturation temperature

cooling rate and agitation rate on the metastable zone width and the effect of supersaturation on the induction period were explored

respectively. The results showed that the crystallization metastable zone width became narrow with rising saturation temperature and agitation rate

and decreasing cooling rate. The apparent nucleation series m and the nucleation rate equation were given. Furthermore

the experimentally measured crystallization induction period decreased with increasing supersaturation S. The solid-liquid interfacial tension of L-tartaric acid in water was calculated at 20℃ and 25℃ on basis of the classical nucleation theory and induction period data.