calcium-based sorbent can circularly capture low concentration co_2 effectively in flue gas,and release high concentration co_2 by raising temperature. but the disadvantage of calcium-based sorbent was sintering seriously with the times of cyclic calcination/carbonation,so that carbonation rate declined rapidly. if only using natural calcium-based sorbent as capture agent,the consumption of limestone is too large. this paper was based on the flue gas in cement industry,and used attapulgite which is abundant in the nature and with the one dimensional structure to modified the surface of limestone,with the effect of anti-sintering and carbonation rate (x_n) was improved. the results showed that: attapulgite physical adsorption to co_2 made contribution to the improvement of calcium-based sorbent carbonation rate (x_n),however,the contribution was less than the improvement of sintering resistance;carbonation rate (x_n) of attapulgite modified larger particle size sorbent was better; kept the particle size of calcium-based sorbent and reduced to particle size of purified attapulgite,its modified effect was further enhanced.