The invention provides a catalyst used for methanation of carbon dioxide, a preparation method therefor and applications thereof. The catalyst employs precious metal Ru or Rh as a main catalytic activity component, employs one or more selected from elements of the I and II main groups and the II, III and VII subgroups as auxiliary agents, and employs one or more selected from SiO2, TiO2, Al2O3, CeO2 and ZrO2 as carriers. The above catalyst is used in graininess or the carriers, the auxiliary agents and the activity component are subjected to coating (wall loading) on a whole structural catalyst and metal honeycombs. The catalyst has characteristics of high activity and selectivity and wide temperature and pressure operation windows. The catalyst can be used for hydrogenation methanation removal of CO2 in a space station, then generated H2O is subjected to electrolysis, and circulation supply of oxygen is achieved. The catalyst also can be used for processes of other CO2 conversion utilization of coal-made natural gases and process gases and the like and new energy development and energy saving and emission reduction are achieved.