The invention discloses a chromium base catalyst, and a preparation method and a use thereof, and belongs to the field of chemical synthesis. The precursor of the catalyst is composed of 90-99.9mass% of a trivalent chromium compound and 0.1-10mass% of a silicon-containing compound, wherein the trivalent chromium compound is chromic oxide or chromium hydroxide, and the silicon-containing compound can be zinc silicate, nickel silicate, magnesium silicate, aluminum silicate, zirconium silicate, barium silicate, bismuth silicate, ammonium fluorosilicate, nickel hexafluorosilicate, zinc fluorosilicate, magnesium fluorosilicate, aluminum fluorosilicate or calcium fluorosilicate The chromium base catalyst has the advantages of large specific surface area, effective inhibition of carbon formation, and long service life, is mainly used for gas phase catalysis of reactions for preparing hydrofluorocarbons or fluorinated alkenes from halogenated hydrocarbons or halogenated alkenes at a high temperature, and can also be used for gas phase catalysis of reactions for preparing hydrofluoroalkenes through hydrogen fluoride removal of hydrofluorocarbons at a high temperature.