Pinus yunnanensis is an endemic tree species in Southwest China. P. yunnanensis forest is a typical representative of warm coniferous forest, mainly distributed in the central Yunnan plateau. Whether P. yunnanensis populations can self-renew or not will affect the vegetation dynamics in central Yunnan. Clarifying the structure and dynamics of undisturbed P. yunnanensis populations is an important basis for studying the sustainable development of P. yunnanensis forests. The P. yunnanensis forest in the Yunlong Tianchi Nature Reserve in Yunnan Province is a relatively pristine forest without human interference. In this study, the static life table, survival curve, survival function curve and spectral analysis of P. yunnanensis natural populations were analyzed in Yunlong Tianchi Nature Reserve. The results demonstrated that the age structure of P. yunnanensis in Yunlong Tianchi National Nature Reserve was inverted J-type, the dynamic index of population age structure change in quantity V_pi was 28.29%, the dynamic index of population age structure in the presence of external disturbance V'_pi was 1.77%, the population dynamic index V_pi and V'_pi were both greater than 0, and the probability of the population assuming risk under external disturbance was P_max 6.25%. The above results indicated that the P. yunnanensis population is a growing population structure with some resistance to disturbance. Furthermore, the P. yunnanensis population had a survival curve tending to the type of Deevey-II, and the survival analysis found that the survival rate, cumulative mortality rate, mortality density and hazard rate varied greatly from Ⅰ to Ⅶ age classes (diameter at breast height<35 cm), and stabilized from Ⅶ to XVI age classes (diameter at breast height 35-80 cm). The spectral analysis exhibited that the population dynamics of P. yunnanensis followed one major trend, and the Ⅲ age class (diameter at breast height 10-15 cm) was the main stage affecting the population size. The above results reveal that the number of individuals in the lower age classes of P. yunnanensis populations in the Yunlong Tianchi Nature Reserve fluctuates greatly, with more individuals dying and the upper age classes declining. It is suggested that the young and middle-aged natural P. yunnanensis forests in the Yunlong Tianchi Nature Reserve can be nurtured and intercut to promote their population growth, development and renewal. Based on all these results, the population of P. yunnanensis was found to remain sustainable in the long term, although it fluctuates in the middle and lower ages.