Abstract: Bamboo fiber saturation point (FSP) has an important guiding significance for bamboo processing and utilization. In this paper, the FSP of moso bamboo and its variation with age were studied systemic by mechanical methods. The results indicated that the data of FSP which studied by Boltzmann curve fitting mechanical properties was reasonable, but FSP of four mechanical properties at the same age was slightly different. However, the changes of the FSP with age indicate the same variation tendency, namely FSP decreases quickly from 0.5 a to 1.5 a and then remain rather stable from 1.5 a to 4.5 a.