Abstract: Three different stand ages of Robinia pseudoacacia plantations, including young plantation (5-10 years old), middle-age plantation (11-15 years old), and mature plantation (21-30 years old), were selected as the objects, to explore the contents of C, N and P and their ecological stoichiometry characteristics in roots, stems, leaves and litter. The results showed that carbon, nitrogen and phosphorus contents varied in the range of 376.74-486.67, 8.66-29.70 and 0.79-1.95 g·kg^-1, respectively in different components of R. pseudoacacia plantations with different ages. There was a low variability of C content, a high variability of P content. The high C content was found in middle-age plantation, and the high N and P contents were found in mature plantation. The high C, N and P contents were found in leaves, and the low N content was found in stems for diffe-rent-aged R. pseudoacacia plantations. C/N, C/P and N/P in different components of R. pseudoacacia plantation were 15.74-53.40, 242.47-606.39 and 8.10-20.57, respectively. C/N, C/P and N/P of stems in mid-mature plantation and young plantation were significantly higher than those in mature plantation. C/N and C/P were high in stems, and C/N and C/P was low in leaves in diffe-rent-aged R. pseudoacacia plantations. There was no correlation among carbon, nitrogen and phosphorus contents in leaves and roots of R. pseudoacacia plantations, but significant positive correlation between the nitrogen content and phosphorus content in litter and stems. It indicated that the litter and stems were built on the proportional input of nitrogen and phosphorus elements. Compared with the global scale, R. pseudoacacia plantation in the Loess Plateau had the high carbon storage capacity, abundant nitrogen content and relative lack of phosphorus, which became the major limi-ting factor for growth of R. pseudoacacia plantation.