The invention discloses eggplant flavanone 3-hydroxylase SmF3H as well as a gene and application thereof; nucleotide sequences of cDNA and gDNA of the gene are respectively as shown in SEQ ID NO.1 and SEQ ID NO.2; and the amino sequence coded by the gene is as shown in SEQ ID NO.3. The nucleotide sequence of the promoter sequence of the gene is as shown in SEQ ID NO.4. The gene is expressed in root, stem, leaf, flower, peel and pulp, and the expression amount in the stem is significantly higher than that in other tissues. Under low-temperature stress, the expression amount achieves a maximum value at 12thh, which is 2.34 times as much as that unprocessed. An over-expression vector of the eggplant SmF3H is constructed and is converted into arabidopsis thaliana, discovering that anthocyanin contents in stem and fruit pod are significantly improved. The invention provides theoretical basis for improving plant quality by virtue of gene engineering technology in the future so as to obtain highly anti-oxidative medicines or food; therefore, the eggplant flavanone 3-hydroxylase SmF3H is quite high in application value.