Abstract：Six generations（P1, P2, F1, BC1, BC2 and F2）derived from 2 crosses q-1×23-4G（cross 1）and q-1×A-7（cross 2）were used to investigate inheritance of the 1st node female flower and early flowering date in the summer squash（Cucurbita pepo L.）by using major gene and polygene mixed inheritance model. The results showed that the 1st node female flower was controlled by D-2 model and the early flowering date was controlled by B-1 model. Genetic effects of the 1st node female flower of 2 crosses were mainly additive effect of major gene. But additive effect and additive × dominant epitasis effect mainly played role on early flowering date of 2 crosses. Early flowering date of cross 1 was mainly controlled by additive effect of the second major gene. Heritability values of environmental effect were relatively higher on the 1st node female flower and the early flowering date. These results indicated that directional selection should be effective on the 1st node female flower, but selection for early flowering date characteristics should be carried out on high separated generations.