Abstract: Freezing-thawing action will affect the mechanical and structural characteristics of sludge solidified light soil. In order to study the dynamic characteristics and structural evolution of sludge solidified light soil under different freezing-thawing cycles and freezing temperatures, dynamic triaxial tests and consolidation tests were carried out on the sludge solidified light soil after freezing-thawing cycles. The test results show that the dynamic stress-strain curve of light soil solidified by sludge is of weak strain hardening type under the action of freezing-thawing cycle. The dynamic strength and deformation of sludge solidified light soil decrease with the increase of freezing-thawing times （n） and the decrease of freezing temperature （T）. The first four freezing-thawing cycles have a great influence on the deformation and dynamic strength of solidified soil, and the dynamic characteristics of soil tend to be stable after eight freezing-thawing cycles. The influence of freezing-thawing cycle on is essentially the influence on soil structure. The variation law of freezing-thawing structural potential （m_dσn） of solidified soil is similar to that of dynamic strength, showing the decrease with the increasing freezing and thawing times and the decrease with the decreasing freezing temperature. The number of freezing-thawing cycles is the main factor affecting the dynamic characteristics and structure of sludge solidified light soil, and the freezing temperature is the secondary factor.