CO2 breakthrough pressure is a key parameter of caprock sealing efficiency evaluation for CO2 geological storage technology, which is one critical technology for greenhouse gas mitigation. It is mainly acquired by laboratory tests, including indirect and direct methods. The indirect methods mainly consist of mercury intrusion porosimetry. The direct methods consist of continuous injection method, step-by-step method, displacement method and pulse decay method (residual capillary pressure approach). Based on a literature review of existing laboratory breakthrough pressure measurement methods, measurement principles, testing procedures, error sources analysis and application ranges are introduced. Mercury injection method can obtain breakthrough pressure quickly, however, its measuring accuracy is comparatively low due to the impacts of such factors as conversion from mercury-air condition into CO2-brine condition including surface tension and contact angle, damage of porous structures, and so on. Step-by-step approach is based on the definition of breakthrough pressure. This approach has a high accuracy, but it is time-consuming. It always costs several months to conduct one test on caprock samples with a low permeability. Continuous injection approach also has a good accuracy, but it could over-estimate the CO2 breakthrough pressure due to the neglect of pressure gradient in the water phase and the delay between flow rate change and pressure change. Displacement method is widely used in natural gas industry in China. The experiment process is easy and timesaving; however, conversion and correction of the experiment results are complicated and high experience-dependent. Pulse decay method, which stems from step-by-step approach, has certain accuracy and efficiency. However, the difference between snap-off pressure and breakthrough pressure is still not clearly explained. At last, the application range and research demands of CO2 breakthrough pressure measurements are recommended based on the measurement principles, experiment procedures and error sources.