The invention relates to the synthetic field of organic intermediates, and discloses a preparation method of 2,4,4-trimethyl-3-hydroxymethyl-2-cyclohexene-1-ketone. The method comprises the following steps: mixing 4-oxo-Beta-ionone taken as a raw material with an ozonation reaction solvent; then performing an ozonization reaction at a reaction temperature within -80 DEG C to -20 DEG C; leading nitrogen into the mixture after the ozonization reaction so as to evacuate ozone; performing a stirring reaction for 1 to 2 hours at the reaction temperature within -10 DEG C to 30 DEG C by adding a reducing agent; performing distillation under a normal pressure so as to recycle the ozonation reaction solvent; and then performing decompression and fraction, thereby obtaining the 2,4,4-trimethyl-3-hydroxymethyl-2-cyclohexene-1-ketone. The 2,4,4-trimethyl-3-hydroxymethyl-2-cyclohexene-1-ketone is prepared from the 4-oxo-Beta-ionone which is taken as a raw material and is sequentially ozonized and the reduced. The method has the advantages of being simple and direct in process routes, good in selectivity, high in yield, rapid in reaction speed, simple in aftertreatment and the like. Thus, the method conforms to the tendency of environmental-friendly chemical industry in nowadays and has a great industrial value.