The invention discloses a microstructure detection method for freezing-thawing damage of cement-based materials. According to the microstructure detection method for the freezing-thawing damage of the cement-based materials, the freezing and thawing cycle experiment method conforming to the national standard is not adopted, microstructures of the cement-based materials before and after the freezing-thawing damage can be obtained by changing the surface sealing states of the cement-based material test samples and freezing and thawing cycle systems, and utilizing a microstructure detection measure, namely an X-ray tomography imaging technology, wherein the surface sealing states include full epoxy resin sealing, half epoxy resin sealing, full preservative film package no preservative film package and no sealing, and the freezing and thawing cycle systems include gas freezing and thawing, oil freezing and thawing, and single-surface water freezing and thawing, and microfracture information caused by the freezing and thawing cycle can be quantitatively analyzed, so that the basis is provided for the mechanism research of freezing-thawing damage of the cement-based composite materials.