The content of soluble solids in cucumber fruit is a key indicator to measure its nutritional quality and flavour characteristics. In order to elucidate the genetic regulation mechanism of this trait， the F₂ segregated population constructed from the inbred line 21A140 with high soluble solids content and the inbred line 17s-132 with low soluble solids content was selected in this study， and the soluble solids content of cucumber fruits was mapped by BSA-Seq technology. The results showed that the soluble solids content of cucumber fruit was in line with the two-pair additive-main gene genetic model. QTL mapping analysis showed that 9 significant association regions were successfully identified on chromosomes 1 and 6，109 candidate genes were obtained， and 8 candidate genes related to soluble solids content were screened by gene annotation. qRT-PCR analysis showed that the majority of candidate genes were significantly differentially expressed in the fruits of 21A140 and 17s-132， among which CsaV3_1G027950（located on chromosome 1）， CsaV3_6G004010 and CsaV3_6G012740（located on chromosome 6）were involved in biological processes such as sucrose metabolism， carbohydrate metabolism and transcriptional regulation， which were speculated to be the key candidate genes for regulating the soluble solids content of cucumber fruits. This study provides a theoretical basis for the cloning and molecular marker development of genes regulating soluble solids content in cucumber fruits.