As an important tool for clarifying the mechanism of chlorophyll biosynthesis and chloroplast development in plants, leaf color mutants are of great significance for exploring the process of plant growth and development. In this study, the green leaf tomato material ""CR11A"" and the light yellow leaf tomato material ""CH09-805"" were used as parental materials to constrct the genetic population and clarify the inheritance pattern. The chloroplast ultrastructure were observed and chlorophyll content were determined in leaf with different colors. BSA-Seq and molecular marker screening were used to map the leaf color gene and analyze the candidate genes. The results showed that the leaves of F1 plants were green, and segregation ratio of 12 (green):3 (light yellow):1 (golden yellow) were observed in the leaves of F2 population, indicating that the tomato leaf color was controlled by two pairs of genes with a dominant epistasis effect. Through chloroplast ultrastructure observation and chlorophyll content determination, it was found that the chloroplast ultrastructure of the golden leaves was severely damaged, and the chlorophyll content of golden leaves was significantly lower than that of light-yellow and green leaves. The tomato leaf color gene Sllc1 was mapped to a physical distance of 114.53 kb in chromosome 7 using BSA-Seq and molecular marker screening, and a total of 13 genes were included in the interval. Combined with the information of gene annoation and variation, the Solyc07g053630 and Solyc07g053640 were predicted as the candidate genes of Sllc1. The results of this study obtained the candidate gene for , which would lay an important material foundation and genetic resources for the analysis of the molecular mechanism of tomato leaf color formation.