The fundamental basis of isotope separation is based on their different physical and chemicalnature, which is due to the different quality and structure of isotope atom.But the number of extranuclear electron is the same as their distribution, the difference between their physical and chemical nature is tiny. Though it is very difficult to separate stable isotope, many effective methods have beendeveloped in recent 50 years, such as the methods of distillation, diffusion, gas centrifuge separation, electrolysis, electromagnetic separation, biologicalseparation, photochemical and laser separation,etc. Those methods have a little effect of separation, but are scarcely adopted in the manufacture of stableisotope, because the production needs not only the higher separation quotiety,but also the simple and reliable equipment, low cost, safe operation, etc. Inorder to meet the requirements, The center explores and improves the techniques and methods continually, various techniques and methods to separate stableisotopes have been developed such as the chemical exchange,waterdistillation,heat diffusion method,low distillation method.