Abstract The effects of manganese salts including Mn(NO 3 ) 2 and MnCO 3 on CO 2 capture performance of calcium-based sorbent during cyclic calcination/carbonation reactions were investigated. Mn(NO 3 ) 2 and MnCO 3 were added by wet impregnation method. The cyclic CO 2 capture capacities of Mn(NO 3 ) 2 -doped CaCO 3 , MnCO 3 -doped CaCO 3 and original CaCO 3 were studied in a twin fixed-bed reactor and a thermo-gravimetric analyzer (TGA), respectively. The results show that the addition of manganese salts improves the cyclic carbonation conversions of CaCO 3 except the previous cycles. When the Mn/Ca molar ratios are 1/100 for Mn(NO 3 ) 2 -doped CaCO 3 and 1.5/100 for MnCO 3 -doped CaCO 3 , the highest carbonation conversions are achieved respectively. The carbonation temperature of 700–720 °C is beneficial to CO 2 capture of Mn-doped CaCO 3 . The residual carbonation conversions of Mn(NO 3 ) 2 -doped and MnCO 3 -doped CaCO 3 are 0.27 and 0.24 respectively after 100 cycles, compared with the conversion of 0.16 for original one after the same number of cycles. Compared with calcined original CaCO 3 , better pore structure is kept for calcined Mn-doped CaCO 3 during calcium looping cycle. The pore volume of calcined MnCO 3 -doped CaCO 3 is 2.4 times as high as that of calcined original CaCO 3 after 20 cycles. The pores of calcined MnCO 3 -doped CaCO 3 in the pore size range of 27–142 nm are more abundant relative to clacined original one. That is why modification by manganese salts can improve cyclic CO 2 capture capacity of CaCO 3 .