To improve the stability of CaO adsorption capacity for CO2 capture during multiple carbonation/calcination cycles, modified CaO-based sorbents were synthesized by sol-gel-combustion-synthesis (SGCS) method and wet physical mixing method, respectively, to overcome the problem of loss-in-capacity of CaO-based sorbents. The cyclic CaO adsorption capacity of the sorbents as well as the effect of the addition of La2O3 or Ca12Al14O33 was investigated in a fixed-bed reactor. The transient phase change and microstructure were characterized by X-ray diffraction (XRD) and field emission scanning electron microscop(FSEM), respectively. The experimental results indicate that La2O3 played an active role in the carbonation/calcination reactions. When the sorbents were made by wet physical mixing method, CaO/Ca12Al14O33 was much better than CaO/La2O3 in cyclic CO2 capture performance. When the sorbents were made by SGCS method, the synthetic CaO/La2O3 sorbent provided the best performance of a carbonation conversion of up to 93% and an adsorption capacity of up to 0.58 g-CO2/g-sorbent after 11 cycles.