The invention provides a carbon steel flux-cored wire for nuclear power engineering and a preparation and an application thereof and belongs to the field of welding materials. The flux core of the carbon steel flux-cored wire which is provided by the invention comprises the following ingredients in percentage by weight: 40-60% of TiO2, 15-30% of Mn, 1-15% of SiO2, 0.01-0.5% of Mo, 0.1-1.0% of ZrO2, 0.1-4% of A1 and Mg, 0-0.08% of fluoride and the rest of iron powder. The filling rate of the flux core is 10-20%. Through the carbon steel flux-cored wire which is provided by the invention, the integral performance of a weld joint is effectively improved, and the problem that the metal low temperature tenacity of the weld joint is insufficient is solved. The carbon steel flux-cored wire can be widely applied to the welding of steel structures in the nuclear power engineering.