Since 1978,artificial snow augmentation by aircraft silver iodide seeding to the winter stratiform clouds have been conducted continuously along Tianshan mountains in northern Xinjiang.The freeze injury comparison of the winter wheat was made between the 18 unseeded years and the 17 seeded years.The average annual freeze injury area has been decreased over 80% during seeded period.Tree main factors which includ wheat seeds improvement and wintertide temperature increase as well as artificial snow augmentation have been analysed.The obtained results suggest that cloud seeding is a primary factor.