Porous liquids (PLs) based on ZIF-8 with different particle sizes for CO2 capture were prepared through particle size control strategy. Combined with theoretical and experimental data of CO2 adsorption, it was confirmed that PLs had permanent pore structure. Viscosity experiments showed that different PLs have excellent fluidity. The three porous liquids of different sizes showed no aggregation and deposition after placement at room temperature for 60 d or centrifugation at 4500 r/min for 5 min, indicating that the PLs of different sizes have excellent stability. The influence of ZIF-8 sizes on the CO2 capture capacity, rate, CO2/N2 selectivity and cycling stability of PLs was studied, and the CO2 adsorption kinetics of PLs with different sizes were studied. The result showed that the CO2 adsorption by PLs based on ZIF-8 with different particle sizes includes physical adsorption and chemical adsorption. Among them, The ZIF-8-PLs(43) with the ZIF-8 size of 43 nm had the highest saturation CO2 adsorption capacity with 63.0 mg/g; ZIF-8-PLs(145) exhibited a faster CO2 adsorption rate with a kinetic constant of 1.91×10-3 g/(mg?min); ZIF-8-PLs(1400) had the highest CO2/N2 selectivity, which was 4.8 times higher than that of ZIF-8-PLs(43); All three PLs had excellent cycling stability after 5 cycles.