To study the dynamic characteristics and microstructure of nano-CaCO3 remolded soft clay under cyclic loading, GDS dynamic triaxial and NMR tests were conducted to analyze its dynamic stress-strain, dynamic elastic modulus, damping ratio, and micro pore changes. The results show that as the content of nano-CaCO3 increases and the confining pressure increases, the dynamic strain of the remolded soft clay gradually decreases and the dynamic elastic modulus gradually increases; The increase in consolidation stress ratio leads to a decrease and then an increase in dynamic strain of nano-CaCO3 remolded soft clay, and an increase and then a decrease in dynamic elastic modulus; The increase in confining pressure and consolidation stress ratio can effectively reduce the damping ratio of the soft clay; There is a significant nonlinear relationship between the hysteresis energy dissipation of soft clay and the dynamic strain curve; The main peak and peak area of the T2 distribution curve of nano-CaCO3 soft clay are significantly reduced compared to plain soft clay, and the decrease in pore ratio makes the soil structure more stable. The obtained dynamic characteristics of remolded soft clay based on nano-CaCO3 provides some reference for practical engineering.