The color of beans changes from turquoise to blue-green, which can be easily cut off, and the texture is soft and ripe. Kidney bean is an annual vegetable of cowpea, also known as cowpea, cowpea and cowpea. Rich in protein and carotene, it has high nutritional value and good taste. It is one of the popular vegetables widely cultivated in northern China, and its popularity ranks first among all kinds of vegetables.