Abstract: In this study，cowpea cultivars with purple flower were selected as female parent and white flower one as male parent，F₁ hybrids were obtained by hybridization，F₂ generation derived from selfcross of F₁. Both the parents and F₂ generation were used as the experimental material. During the cowpea blooming stage，field investigation was carried out on recording the flower color of the parents and their F₂ offspring. In the field，the color of the F₂ offspring showed purple flower（female type），white flower（male type）and light purple（middle type）. With the χ² test，the separation is consistent with the Mendelian inheritance law，and its genetic separation ratio is modified to 12∶ 3∶ 1. The hereditary pattern of cowpea corolla conforms to the genetic quality traits，and there may be a pair of non-allelic gene P and W . The P gene controls the formation of purple flower，the W gene controls white flower. As long as P gene exists，the white corolla controlled by W gene can not demonstrate，and vice versa. It is deduced that gene P covers up the performance of another non-allelic dominant gene W ，which is manifested as dominant epistatic effect. In this study，we explored the variation of thecowpea color trait and its inheritance characteristics in order to guide the breeding and production of legumes.

Key words: cowpea, corolla color, genetic variation, Mendel inheritance