Abstract: Feed conversion ratio (FCR, %) is an important economic trait of turbot (Scophthalmus maximus). Improving feed conversion ratio through selective breeding can effectively reduce the breeding cost and improve the breeding profit, thus promoting the development of the industry. Microsatellite markers are commonly used in molecular marker-assisted breeding of fish. In order to screen out microsatellite markers related to feed conversion ratio of S. maximus and improve breeding efficiency, 300 juvenile S. maximus were used as experimental material in this study, and individual feed conversion ratio was measured through a special cage culture system. The 30 samples with the highest and lowest feed conversion ratios were selected as the high feed conversion ratio group (group H) and the low feed conversion ratio group (group L). 40 pairs of microsatellite primers were used to amplify the DNA mixed pools of S. maximus from groups H and L by PCR. The genotypes of individual PCR products of the two groups were counted, and the loci with different allele fragments between the two pools were screened. Through further population verification and family verification, the correlation between microsatellite loci and feed conversion ratio of S. maximus was analyzed. The results showed that the allele of microsatellite locus YSKr148 at 238 bp was significantly positively correlated with the feed conversion ratio of S. maximus (P<0.01), and the correlation coefficient reached 0.359. The feed conversion ratio of the positive group was significantly higher than that of the negative group in family verification (P<0.01). In this study, for the first time, molecular markers significantly related to feed conversion ratio of S. maximus were screened, which provided a basis for studying the genetic basis and related molecular mechanism of this trait, and laid a foundation for molecular marker-assisted breeding of this trait.