A fusiform fruit mutant HL-fu was found from inbred line HL of Cucurbita maxima. There was obvious biological characteristic variation on a lot of organs of the mutant, such as flower, fruit, stem. The residual degree of the stamen from female flower and the pistil from male flower of the mutant were more than the wild type one. Its fruit was fusiform, it was five times on the fruit shape index of the mutant than the wild type one. The arrangement status of the mutant internode was long short alternative distribution, the phyllotaxis was similar to the opposite phyllotaxis. The reciprocal cross F1 was constructed by crossing mutant HL-fu and wild type HL, the genetics of the groups of cross F2, BC1(P1)1F1 and BC1(P2)F1 were analyzed. We speculated that the variation type was recessive mult-effect single gene mutant, the mutant character was controlled by a pair of recessive nuclear gene fu. We discussed the potential value of fusiform fruit mutant on the pumpkin breeding and the basic study.