Genetic population derived from a line ‘Agol’（dwarf ）and ‘Xue1’（vine）was used to analyze the inheritance of internode length in cucurbita maxima. The result showed that dwarf and vine is determined by nuclear genes. Developmental reversal of dominance were found in this study. The genetic model showed that the internode length were controlled by two major gene (genetic model E1) in early development and reversal of dominance stage, and the major gene can explain more than 70% variation. But in the late development stage, it were controlled by a single gene (genetic model D4), which explaining 10% variation. The results also proved that in late development stage environment has significantly effect on internode length development. This study will provide more information for dwarf-type genetic mechanism; also the results will lay a good foundation for cucurbita maxima dwarf-type breeding.