The effects of PEG6000 on the growth and the contents of vindoline(VIN)，catharanthine(CAT) and vinblastine(VBL) of Catharanthus roseus seedling were investigated using soil cultivation in the greenhouse．The results showed that the developing trend of the relative water content（RWC）was declining and rising.The developing trend of proline (Pro) content was increasing slowly and increasing quickly with the development of time under the same concentration PEG6000 stress.Combining and optimizing various conditions,35%（V/V） PEG6000 stress on leaves of C.roseus was established.Contrasting with the control,the peroxidase activities increased gradually first and then decreased.Vindoline content decreased gradually then increased while catharanthine content increased gradually then decreased.Vinblastine content increased and reached the highest 0.168 0±0.003 6 mg/g(FW) on the 24th hour.The results showed that peroxidase activities could regulate the transform from monomeric indole alkaloids to bis-indole alkaloids under the osmosis stress.