The hydrogenation of carbon dioxide to lower (C 2 –C 4 ) olefins is an important reaction for the utilization of CO 2 as a carbon feedstock for the production of building-block chemicals. We found that an Fe/ZrO 2 catalyst could catalyze the hydrogenation of CO 2 , but the main products were CH 4 and lower (C 2 –C 4 ) paraffins. The modification of the Fe/ZrO 2 catalyst by alkali metal ions except for Li + significantly decreased the selectivities to CH 4 and lower paraffins and increased those to lower olefins and C 5+ hydrocarbons, particularly C 5+ olefins. The modification by Na + , K + , or Cs + also increased the conversion of CO 2 . The best performance for lower olefin synthesis was obtained over the K + -modified Fe/ZrO 2 catalyst with a proper K + content (0.5–1.0wt%). Among several typical supports including SiO 2 , Al 2 O 3 , TiO 2 , ZrO 2 , mesoporous carbon, and carbon nanotube, ZrO 2 provided the highest selectivity and yield to lower olefins. Our characterizations suggest that the modification by K + accelerates the generation of χ-Fe 5 C 2 phase under the reaction conditions. This together with the decreased hydrogenation ability in the presence of K + has been proposed to be responsible for the enhanced selectivity to lower olefins.