Abstract: Seed dormancy is pervasive in advanced plants, and is a biological characteristic that plants possess over long-term natural selection. Pinus bungeana Zucc. is an endemic species in China and has high ornamental value. It reproduces mainly through seeds; however, the seeds with deep dormancy cause difficulties in seedling breeding. In this study, the reasons for dormancy of P. bungeana seeds and the methods of dormancy breaking are summarized. The causes of dormancy mainly include the development of embryo in a mature seed; the presence of different kinds and amounts of germination inhibitors in the seed coat, paper layer, and endosperm; the presence of abscisic acid, which possesses strong inhibitory ability, in these three parts; mechanical resistance and permeability of the seed coat to germination; and endogenous hormones. The common methods of dormancy breaking are cold stratification, long-time flushing, soaking in plant hormones, chemical treatment, mechanical treatment and environmental condition treatment.