Abstract: In order to measure accurately the content of residual austenite in GCr15 bearing steel,it is necessary to determine the carbide content firstly. Calculation method,metallographic method and electrolytic extraction method were used to measure the carbide content,and these methods were compared . The results show that,the volume fraction of carbide in annealed GCr15 bearing steel was between 13.51% and 16.61%. Metallographic method only could be used to estimate the carbide content for its larger error,and calculation method could be used as a reference method because of the phase content obtained under the condition of equilibrium thermodynamics,while the electrolytic extraction method is a relatively accurate quantitative method for measuring carbide content in GCr15 bearing steel.