P. tabulaeformis is one of the major forest vegetation species in the warm temperate zone of China. It is of great scientific value to accurately calculate the biomass of natural P. tabulaeformis forest and to characterize the spatial distribution for assessing forest ecological services in the aspects of fixing carbon and releasing oxygen, and nutrient accumulation. To date, the pattern of biomass and distribution across a chronosequence of P. tabulaeformis natural secondary forest is poorly documented. The objectives of this study were to examine the biomass and distribution of the main ecosystem components in an age sequence of four P. tabulaeformis natural secondary forest stands (young, middle-aged, immature, and mature) in the Liaoheyuan Nature Reserve of Pingquan County, Hebei Province. Within each stand, biomass of understory (including shrubs and herbs) and litter was determined from plot-level inventories and destructive sampling. The allometric equations using diameter at breast height (DBH) and height (H) have been developed to quantify (above- and belowground) tree biomass. The results are as follows. (1) The size of the stand biomass follows the order of mature (397.793 t/hm²) > immature (242.188 t/hm²) > middle-aged (203.801 t/hm²) > young (132.894 t/ hm²); (2) Biomass size of the tree layer ranks from high to low as mature (373.128 t/hm²) > immature (224.991 t/hm²) > middle-aged (187.750 t/hm²) > young (119.169 t/hm²). The order of biomass size of tree components is slightly different; young and immature forests follow the order of stem > root > branch > needle > bark > pine cone, while middle-aged and mature forests order as stem > root > branch > bark > needle > pine cone. The stem is the largest contributor to the total tree biomass, and the order of proportion is middle-aged (66.25%) > immature (64.38%) > mature (62.09%) > young (38.41%); pine cones contribute least, following the order of mature (1.02%) > young (0.88%) > immature (0.72%) > middle-aged (0.53%). The total root biomass of four stands ranged from 18.315 t/hm² for the middle-aged stand to 44.849 t/hm² for the mature stand, and the root component biomass ranks on the whole as root pile > coarse root > big root > fine root > small fine root; (3) The biomass of shrub layer orders as mature (0.861 t/hm²) > immature (0.790 t/hm²) > middle-aged (0.559 t/hm²) > young (0.401 t/hm²), and the order of organ biomass is root > stem > needle; (4) The biomass of the herb layer ranks as young (3.058 t/hm²) > immature (2.017 t/hm²) > middle-aged (1.220 t/hm²) > mature (1.181 t/hm²), and the biomass of underground portion is greater than that of the aerial parts; (5) Litter layer biomass follows the order of mature (22.623 t/hm²) > immature (14.390 t/hm²) > middle-aged (14.272 t/hm²) > young (10.265 t/hm²), and the decomposition layer > semi-decomposed layer > full decomposition layer. (6) The comparison of biomass of the four age groups at all levels shows the consequence of tree layer > litter layer > herb layer > shrub layer. Across this chronosequence, the tree layer biomass accounts for 89.67%, 92.13%, 92.90% and 93.80% of the total tree biomass for young, middle-aged, immature, and mature stands, respectively.