Solid-liquid biphasic absorbents feature the advantages of easy separation and operation since the solid products after CO2 capture can be separated by static precipitation. However , most of the existing absorbents require organic phase separators to regulate the phase transition, resulting in bottlenecks such as volatile loss of phase separators and high viscosity of rich liquid phase. ln this work, a novel amine-water binary solid-liquid biphasic absorbent was constructed, which can generate solid-liquid phase change behavior after CO2 absorption in the aqueous solution without adding phase splitter. Absorption experiments showed that the total absorption capacity of IPDA -H2O could reach 0.85 mol CO2·mol-1 with a concentration of 1.00 mol·L-1 and an absorption temperature of 313.15 K. After saturated absorption, CO2 became enriched into the lower solid phase of the solution, with the rich phase accounting for 43.60% of the total solution volume and containing 93.98% of the total absorption loading. The viscosity of the CO2-lean phase was as low as 1.08 mPa·s. After hot-melted, the solid products were regenerated at 393.15 K for 60 min, and the regeneration efficiency was 98.31%. Even after 5 cycles of absorption and desorption , the regeneration capacity remained above 80% of its initial capacity, demonstrating good regeneration stability. The spectra of 13C NMR showed that most of the IPDA-carbamate and its decomposition product, bicarbonate, were mainly concentrated in the rich solid phase, while a small amount of unprecipitated carbamate and water were present in the leanphase. The spectra of the  C NMR indicated that CO, was almost completely released from IPDA-H,O.confirming the good absorption-desorption perforance of the system. Combined with quantum chemical calculations , it was found that the dipole moment of IPDA and H2O were close with each other, indicating similar polarity and high mutual solubility before CO2 absorption. After absorption, the dipole moment of products decreased, and the intramolecular hydrogen bond between the products was higher than that between the product and water. The product lattice energy increased, causing the product carbamate to precipitate from the solution and undengo a solid-liquid phase transition.