Two diverse advanced homozygous inbred lines of cabbage, 01-88 and 02-12, with the significant difference on the main agronomic traits related to plants, were used as the parents to develop a Double Haploid (DH) population containing 189 lines, through microspore culture. Using mixed major gene plus polygene inheritance model, the traits of number of outer leaf (Nol), plant breadth (Pb), plant height (Ph), length of outer leaf (Lol), width of outer leaf (Wol) and primary color of outer leaf (Pcl) in B. oleracea were investigated. The results showed that all the 6 main agronomic traits were continuous, single peak and partial distribution. This demonstrated that 6 main agronomic traits related to plants were quantitative. Except Wol and Pcl, the inheritances of other 4 traits were in agreement with two major genes plus polygenes. The heritability of major genes in descending order were following as Ph(59.16%) > Lol(56.56%) > Nol(55.67%) > Pb(19.56%). Due to the high major gene heritability of Ph, Lol, Nol, they were efficiently used for early-generation selection. Nol-Pb, Lol-Wol etc paired traits were significant positive correlation. Nol-Wol wassignificant negative correlation. The results were facilitated to indirectly select in breeding.