Abstract: Objective To study the chemical intervention method for precancerous squamous epithelial lesions in buccal mucosa of rabbits using alltransretinoic acid（ATRA） and Kanglaite injection. Methods Rabbits were given membrane containing ATRA and Kanglaite injection when a rabbit model of precancerous squamous epithelial lesion was established. Pathological changes were observed with pathological histology and immunohistochemistry. Results Among the 16 rabbits in blank control group, reversion was achieved in 2, the disease became stable in 6, and exacerbation was found in 8, while among the 32 rabbits in treatment group, reversion was achieved in 12, the disease became stable in 15, and exacerbation was found in 5, 12 weeks after treatment with ATRA and Kanglaite injection. Immunohistochemistry showed that the expression levels of PCNA and Bcl-2 protein in rabbits were significantly decreased with reversion of the disease（29/32, 26/32）. Conclusion ATRA and Kanglaite injection can reverse precancerous squamous epithelial lesions in rabbits and may be used as new intervention chemicals.