Abstract: This paper studies the effects of 60Co gamma ray radiation on the transmissivity of severa1 types of optical glasses, namely, barium crown, flint, light flint, dense flint, lanthanum flint and lanthanum crown. Transmission spectra in the range of 400~1 100 nm were recorded after exposure to various doses of radiation up to 200 kGy. The results show that the visible transmission for all samples decreases, while the near-infrared transmission sees a slight decrease except QF3 and LaF3. Although the flint and light flint glasses are optically similar before the irradiation, they show a different transmissivity loss after the irradiation, and light flint glass shows the strongest sensitivity with respect to gamma radiation. When the dose increases to some extent, the transmissivity reaches a steady value, ceasing to decrease.These results may help improving radiation tolerance designs for space optical systems.