The lifespan of botanical fine roots is one of the determining variables of fine root turnover and is vital to terrestrial carbon and nutrient cycle. However, there is no sufficient data and research that has been directly observed or conducted on the lifespan of bamboo fine roots, particularly in the characteristics of Phyllostachys glauca culm and rhizome roots. In this study, rhizoboxes were used to study the fine root growth dynamics of the culm and rhizome roots of Phyllostachys glauca. The results indicate that: (1) Fine root lifespans of culm and rhizome roots had no significant difference. Root lifespans increased as the root order rose. The lifespans of the first-order roots were significantly lower than those of second-order roots, and the lifespans of second-order roots were significantly lower than those of third-order roots. (2) The birth and death of culm and rhizome roots had different seasonal patterns. The birth of rhizome roots was concentrated in July, August, and September. Rhizome roots' birth peaked in July and death peaked in spring (from March to May). For the culm roots, there was no single peak in the birth but small peaks in March, July, and November. Culm roots' death peaked in summer (from June to August). (3) The relations between the fine root lifespan and birth date of culm and rhizome roots differed. Culm roots born in summer had the longest median lifespans while those born in spring had the shortest. Rhizome roots born in spring had the longest median lifespans while those born in winter (from December to February) had the shortest. Our findings indicated that fine roots of culm and rhizome roots had different growth patterns, and their lifespan was closely related to root order and birth date. The study could provide a theoretical basis for bamboo forest production and management.