Purpose: To investigate the effect of polyol pathway on lens epithelial cells apoptosis and the activity of caspase-3 and its reversal by pyruvate in diabetic rats. Methods: 220 Wister rats were divided into 3 groups: control group, model group and treatment group. After streptozotocin (STZ) induced cataract, the treatment group received 2% pyruvate in the diet and drinking. The opacification of lens was detected by microscope every 2 weeks. On 4W, 8W and 12W of the experiment, glucose and sorbitol in the lens were quantified by high-performance liquid chromatography. The percentage of lens epithelial cells undergoing apoptosis was measured by Annexin Ⅴ/PI staining. The activity of caspase-3 was analyzed by Western-blot. Results: Studies show that there was significant increase of glucose, sorbitol in lens of model group, the apoptosis rate and caspase-3 activity of lens epithelial cells were also gradually increase. Pyruvate treatment decreased the levels of sotbitol, glucose, lens epithelial cells apoptosis and caspase-3 activity. The progress of cataract was also significantly delayed. Conclusions: Polyol pathway, possibly through regulation of the activity of caspase-3, can induce apoptosis of lens epithelial cell. Pyruvate ingested orally can effective inhibit diabetic cataractogenesis in rats through inhibit polyol pathway. Purpose: To investigate the effect of polyol pathway on lens epithelial cells apoptosis and the activity of caspase-3 and its reversal by pyruvate in diabetic rats. Methods: 220 Wister rats were divided into 3 groups: control group, model group and treatment group. On 4W, 8W and 12W of the experiment, glucose and sorbitol in the lens were 2 hours after streptozotocin (STZ) induced cataract, the treatment group received 2% pyruvate in the diet and drinking. The percentage of lens epithelial cells undergoing apoptosis was measured by Annexin V / PI staining. The activity of caspase-3 was analyzed by Western-blot. Results: Studies show that there was significant increase of glucose, sorbitol in lens of model group, the apoptosis rate and caspase-3 activity of lens epithelial cells were also gradually increased. Pyruvate treatment decreased the levels of sotbitol, glucose, lens epithelial cells apoptosis and caspase-3 activity. The progress of cataract was also significantly delayed. Conclusions: Polyol pathway, possibly through regulation of the activity of caspase-3, can induce apoptosis of lens epithelial cell. Pyruvate ingested orally can effective inhibit diabetic cataractogenesis in rats through inhibit polyol pathway.