Abstract: To study the genetic regulation of important traits of tobacco leaves of cigar wrapper, the joint segregation analysis method of mixed major-gene plus polygene inheritance model were used to analyze three important traits of tobacco leaves of cigar wrapper at three different growth stages, which include foliar fold, leaf thickness and angle between main and lateral vein. Four generations (P₁, P₂, F₁ and F₂) from the cross between Beinhart1000-1 and ‘Hefengbabayan’ were investigated. The results showed that genetic models and interaction effects showed differences at different developmental stages. The heritability of foliar fold was 42.70% and 57.71% respectively at the rosette stage and budding stage. The heritability of leaf thickness was 64.44% and 50.62% respectively at the budding stage and the stage of central flowering. The major genetic heritability of the angle between main and lateral vein in the budding stage was 90.93%, and polygenetic heritability was 42.55% at the stage of central flowering. It was concluded that the genetic effect of the same trait was different at different stages and environmental conditions. Therefore, the interaction between gene effect and external environment should be noted in cigar breeding.