Naked seed is a mutant discovered in Cucurbita. This trait is controlled by a recessive gene with modifier genes. The naked seed,or hullless seed,has no hard seed shell but a thin layer of green membrane outside of embryo. This makes the nutritious seed very convenient to eat. We review the research, nutrient value, and breeding of this special cucurbit crop. The challenges and future breeding prospects of this trait are also discussed in this article.