Abstract: The paper dealed with the absorbtion and accumulation P nourishmet in mycorrhiza of Dendrobium candidum.The results showed that the effect of P with different origin to the seedling growth was different. The dry weights of treatment 3（ KH2PO4） and treatment 6（ FePO4） were 0.018 and 0.019 g respectively, which were 2.62 and 2.78 times than that of treatment 1. The difference was significant. The effect of different concentration of dissoluble P（KH2PO4） to the mycorrhiza tissue culture seedling of Dendrobium candidum, primarily expressed in seedling height, stem and dry weight etc. Treatment 3 was the most suitable and proper density was 0.25 g· L-1. Compared with treatment 9（CONTROL）, the seedling height, stem and dry weight of treatment 3 were 2.64, 2.16 and 3.87 times respectively. Through the analysis to the N, C, P nutrient absorption and accumulation, treatment 3 was 1.72, 1.40 and 11.53 times than that of CONTROL. The result of test on the effect of different available P to propagational growth of Dendrobium candidum mycorrhiza fungi F9903 showed that, when the culture solution contained 1 mg of P content was 22.76% in KH2PO4, the effect of mycelium multiplication was the best, the dry weight was up to 1.256 mg·mL-1,114.2 times that of its inoculum size. In the pillar type diagram of the dry weight of the symbiosis mycorrhiza fungi hypha and the tissue culture seedling with mycorrhiza of Dendrobium candidum in the different density of P nourishment, the shape of diagram and the trend were similar.