Seed from bean Canavalia gladiata(Jacq.)DC. Plant morphology is an annual semi-erect twining herb with a height of 60 ~100 cm. Three compound leaves alternate; Leaflets are broadly ovoid or ovoid-oblong, about 12cm long and about 8cm wide. Racemes axillary; Calyx lip-shaped; Corolla butterfly, reddish purple, round flag flap, narrow and separated wing flap, curved keel flap; Stamen monomer or 1 stamen is partially separated; Ovary has sparse bristles. The pod is flat and slightly curved, up to 30cm long, with ridges on the edge. The seed is oval, red or brown, and the hilum is about 3/4 of the total length of the seed. The flowering period is from June to July, and the fruiting period is from August to1October. Kidney bean seeds are cultivated in Guangdong, Hunan, Jiangxi, Hubei, Jiangsu, Zhejiang, Anhui, Sichuan and Shaanxi.