Abstract: In this paper, the world’s chief achievements in the mutation breeding of crops, including the development of new crop mutation varieties and new mutants, have been summarized and discussed. As regards new crop mutation varieties, the conditions and characters of crop mutation breeding in various countries,the inducing mutation conditions of various crops, the different mutagens and the improved characters have been analysed.As regards various mutants, their types, such as short culm, early maturity,good quality, resistanced to disease, plant morphology, especial character have been dealt with.Again,the author describes the trends of mutation breeding,by giving an account of the object of mutation breeding, the selection of radiation material, the indirect use of mutants, the repeat treatment by physical and chemical means,the development of orogagated plant,the combination of inducing mutation and in-vitro biotechnique.