99mTc, as one of the important radionuclides in nuclear medical science, was widely used for diseases diagnosis in both developed and developing countries for many years.99mTc can be obtained from both fission-type and gel-type 99mTc generator.Fission-type generator was prepared by Mo-99 separated from fission products of U-235 and gel-type was prepared by irradiating natural MoO3 in reactor, and chem. and phys. processes.This paper briefly describes the manufacturing tech. process of gel-type Tc-99 generator, including the preparation of target containing nature MoO3, the target irradiation in reactor, gel preparation, gel filtration and drying, dried gel cracking, generator loading and activity calibration of generator.The performances of gel-type 99mTc generator, such as elution efficiency, elution profile, the pH, Mo breakthrough, Zr content, radiochem. purity, radionuclide purity, sterility and pyrogenicity of eluate, are also expatiated.Comparing with fission-type 99mTc generator, the defects of gel-type 99mTc generator are enumerated and solutions are recommended.