Many scientists have devoted themselves to CO_2 capture research because of the global warming. Limestone can be used for CO_2 capture in cement industry and had been widely reported. But the surface sintering of limestone during the recycling will was dramatically decrease its efficiency. So here we use some oxides such as MgO,SiO_2 and Fe_2O_3 to modify the morphology of the limestone particles thus to increase the CO_2 capture capability of limestone. The efficiency can be increased 7% ~ 8% after adding 1wt% MgO particles. The CO_2 capture capability and the morphology changes have been proved with TGA,SEM,etc.