Abstract: Eight common domestically and foreign cultivated Cucurbita pepo L. cultivars were selected to study 14 morphological indexes influencing plant type under sunlight greenhouse. And effects of plant type on yield formation was discussed. Results show that the main morphological indexes influencing plant type are plant height, internode length, average leaf area, functional leaf quantity and leaf angle. By using cluster analysis, the tested cultivars are classified into two groups (bush vineⅠand semi-bush vine Ⅱ) and four sub-groups (Ⅰ1, Ⅰ2, Ⅱ1 and Ⅱ2). Plant type has a more important effect on C. pepo yield formation. Total yields of the semi-bush vine cultivars are obviously higher than those of the bush vine cultivars and the yield difference mainly forms in the late growth stage. Path analysis shows that internode length plays an important role in yield formation, and the direct effect of function leaf quantity on yield is the strongest, reaching 1.238 0. In breeding and cultivating high yield C. pepo in sunlit greenhouse, emphasis should be placed on the construction of plant type with over 12 functional leaves, average leaf area of 700~800 cm², average internode length of approximately 3.3 cm and upper leaf angle of 45°~66°.