Chloride ions can penetrate into concrete under chloride salt environment,destroying the passivation film of steel reinforcement and triggering the corrosion of steel reinforcement. Diffusion is the primary mode of chloride ion transport within concrete. The chloride ion diffusion coefficient, the most frequently tested and characterised parameter, quantifies the migration rate of chloride ions within concrete and serves as a crucial indicator for evaluating concrete durability. In this paper, the testing methods of chloride ion diffusion coefficient of concrete at home and abroad are reviewed from the aspects of testing time, applicable strength grade range, testing accuracy and suitable scenarios, the advantages and disadvantages of each method are analyzed and compared, with the correlation between the relevant testing methods established, to provide guidance for testing and evaluating the accurate reflection of resistance to chloride ion penetration of concrete. The results show that the natural diffusion method has high reliability and is suitable for life prediction based on Fick’s second law diffusion model, which is commonly used in the durability assessment of important projects. The ASTM C1202 method and NEL method have short testing times and provide highly distinguishable results for evaluating the chloride ion permeability resistance of concrete, which are commonly used in concrete mixing ratio screening and quality acceptance. The test results of the RCM method are more in line with the test results of the natural exposure conditions. The chloride ion steadystate diffusion coefficient measured by the ACMT method can more accurately reflect the long-term diffusion performance of chloride ions in concrete, making it more suitable for service life prediction and durability design. The Permit method, due to its compact and portable equipment, simple operation and minimal structural damage, is primarily suitable for on-site non-destructive testing.