Abstract: Compared to the fission type ⁹⁹Mo-^99mTc generator, the gel type ⁹⁹Mo-^99mTc generator had the advantages of simple process, easy treatment of radioactive waste and small impact on the environment. This paper mainly discussed the difference between the gel type ⁹⁹Mo-^99mTc generator and the fission type ⁹⁹Mo-^99mTc generator, the research status of reactor produced ⁹⁹Mo and the gel matrix of generator. Moreover, the influence of the gel structure and composition on the performance of the gel type ⁹⁹Mo-^99mTc generator were discussed. Finally a brief summary of the research of ⁹⁹Tc production by using low specific activity ⁹⁹Mo production was presented.