Abstract: Aimed to understand the relation between phosphorus(P)efficiency and photosynthesis as well as carbohydrate distribution, the genotypic differences in growth, P accumulation, inorganic P(Pi)concentration of leaves and photosynthetic physiological parameters for Brassica napus Pefficient genotype 102 and Pinefficient genotype 105 were investigated using a pot experiment with three P levels(P15, P30 and P100). The results showed that photosynthesis parameters of two genotypes decreased significantly at low P levels(P15 and P30)in comparison with high P level(P100). Under low P treatment, Pefficient genotype 102 had higher shoot dry matter and P accumulation. Consequently, the higher Pi concentration of leaves for genotype 102 promoted the photosynthesis and the translation of carbohydrates. Hence, photosynthesis became stronger and more carbohydrates were translated from old to young leaves compared to Pinefficient genotype 105.