Abstract: The concentrations of nutrient(N, P, K, Ca and Mg)of leaves of 27 clones of Catalpa bungei C. A. Meyer leaves were determined by Kjeldahl method, Molybdenum blue colorimetric method and Flame photometry, respectively. Also the correlations between genetic variation of the composition content of N, P, K, Ca and Mg and the growth time of the plants were analyzed. The result suggested that N element content decrease as the plants grow among all the clones. Significant differences were found in the N,K,Mg content among 27 clones while no significant differences were found in P and Ca content among all the clones. Significant correlation was found between the growth of the clones and the content of N element. However, the absorption and utilization of the N element was influenced by the content of P and Ca, P element is conducive to the absorption of nitrogen while the effect of the Ca opposite; in addition, the Mg element could inhibit the absorption of the K element, and promote the P element absorption. The order of C. bungei nutrient requirements of the 5 nutrient elements was: N(16.800 g/kg),P(0.079 g/kg),K(5.740 g/kg),Ca(2.700 g/kg),Mg (0.317 g/kg), respectively.