Abstract: In order to select the different nitrogen nutritional type and barren resistance genotypes of slash pine half-sib families, the right half-sib families were selected to forestation under the different nutritional conditions. To explore the mechanism of absorbing nitrogen differences of different slash pine half-sib families，a hydroponic experiment was carried out to measure the uptake kinetics of nitrogen. The results showed that: there were greater differences of the kinetic characteristics between different families. The maximum absorption rate was in accordance with annual average height, annual average single-tree volume of slash pine’s half-sib Families and ranged as 0-464>0-1027>Ⅱ-101>0-609>CK. Compared with the common varieties, the 0-464 and 0-1027 belonged to high N efficient genotype which were suitable for under high N level. The 0-609 andⅡ-101 belonged to N barren resistance genotypes which were suitable for under low N level. The results provided theoretical basis for selecting the nitrogen barren resistance genotypes and high nitrogen efficiency germplasm resources and high yield cultivation.