Riboflavin is involved in many biochemical processes in organisms,but its effects on abiotic stress responses are still poorly understood in plants. To explore the role of riboflavin in response to abiotic stress in rice (Oryza sativa L.), a japonica rice Kitaake and an indica rice T98B were used as experimental materials to investigate the effects of riboflavin on their response to salt, high temperature,osmotic,alkali, and oxidative stresses. The expression levels of riboflavin biosynthesis genes and stress related physiological indexes were determined intensively in rice under salt and high temperature stresses. The results demonstrated that: (1) Exogenous riboflavin effectively enhanced the tolerance to salt and high temperature stresses, and reduced the tolerance to osmotic stress, but did not affect the tolerance to oxidative and alkali stresses. (2) All the abiotic stresses, especially salt and high temperature, promoted the accumulation of riboflavin to different degrees in rice. (3) Both salt and high temperature stresses induced the expression of riboflavin biosynthesis genes, which promoted the biosynthesis of riboflavin and improved the stress tolerance in rice. These results indicate that abiotic stress can promote the biosynthesis and accumulation of riboflavin in rice,and riboflavin can also enhance the tolerance to salt and high temperature stresses but reduce the tolerance to osmotic stress.