The invention relates to a novel crystal form crystal of 1-(5-bromothiophene-2-yl)-3-(nitrobenzophenone)-2alkene-1-ketone and a preparation method thereof. The novel crystal form crystal is defined by characteristic peaks of a DSC and diffraction angle 2 theta degrees of powder X-ray diffraction patterns, and meanwhile the single-crystal structure is analyzed. P-nitrobenzaldehyde and 2-acetyl-5-bromothiophene are dissolved into a reaction solvent according to a mole ratio, a certain amount of sodium hydroxide solution is dropwise added into the mixture for perform a reaction, suction filtration is carried out on sediment obtained after the reaction, and a filter cake is dried to obtain a dry sample 1; the dry sample 1 is dissolved in an organic solvent at the temperature ranging from 40 DEG C to 50 DEG C, and suction filtration and drying are performed to obtain dry samples 2; a seed crystal with no crack on the crystal surface is selected from the dry samples 2 to be placed into a seed rod, and the seed rod is placed into a solution obtained by dissolving the most remaining dry samples 2 into the organic solvent; after culture is performed for a period of time, the novel crystal form crystal is obtained. The novel crystal form crystal has the higher melting point and SHG coefficient, so that the novel crystal form crystal is wider in application range.