Cobalt-rich ferromanganese crust is a kind of water deposition type Fe-Mn oxide,with an extremely low growth rate of 1 to 2 mm/Ma.The cobalt-rich ferromanganese crust was considered important in studying the long scale environmental change of pale oceanography and its relationship with global structuring and climate change.There have been significant advances in the dating method of cobalt-rich crust through decades of practice,progress in technology of elemental and isotope analysis,and the improvement of instrument sensitivity.This paper systematically sums up the advances in dating methods of cobalt-rich ferromanganese crusts,reviews the advantages and disadvantages of different dating methods and their application conditions,and illustrates a more complete evolution curve of Os composition of global seawater from 80 Ma.Additionally,this paper suggests that combining the Os isotope stratigraphy with the Co empirical model formula is an effective way of dating older cobalt-rich ferromanganese crusts at the present stage.