Abstract: Blueberry (Vaccinium spp.), as an important type of small berry for cultivation, has a unique flavor and rich nutrients. With the continuous exploration of nutritional value, blueberry has become one of the fastest-growing new fruit tree industries in China in recent years, and the growth of consumer demand continues to grow rapidly. As an important quality index of fresh blueberry, fruit firmness directly affects fruit quality, consumer preference, transportability, shelf life and mechanical harvesting ability, and has become an important goal of blueberry breeding. In this paper, the firmness formation characteristics, firmness evaluation methods, influencing factors, and genetic basis of blueberry fruit were summarized, and the new hard-fruited blueberry varieties independently bred in China in recent years were introduced. We pointed out the limitations of blueberry fruit hardness genetic breeding research and put forward research prospects, in order to provide strategies and basis for further genetic improvement of blueberry fruit hardness and breeding of new varieties.