Abstract: Using probability matrix, the efficiencies of 4 different breeding systems, animal cloning, superovulation and embryo transfer, breeding of hybrid animals with desirable phenotype in themselves and multiple testcross, in maintaining general genetic diversity were probed while restoring Mondelian characteristics of fine breed in cattle. The results showed that the ratio between the cull rates of neighboring generations was also the ratio between inbreeding increment and the loss of genetic diversity under different systems. In the restoration of characteristics of the fine breed, system is far higher in efficiency than system III. Using the wild type and 3 mutation types of Drosophila melanogaster as subjects, the selection and breeding process were simulated and the results conformed to theoretic investigation. The findings demonstrated that, in the project to rescue fine breeds in cattle, the multiple testcross system is a better way to reshape the good Mondelian breed characteristics.