Abstract: Rapeseed (Brassica napus) needs enough phosphorous (P) in its early growth stage and thus is very sensitive to P deficiency. Two genotypes of rapeseed, i.e., a P-efficient cv. 97081, and a P-inefficient cv.97009, were used to study the growth, P uptake and utilization, plant P fractions and the activity of acid phosphatase (APase) under normal and low P nutrient status using soil pot and hydroponic experiments. The results showed that cv. 97081 possessed high effiency of P uptake and utilization since its dry biomass and P accumulation increased by 85.7% and 50.0%, respectively, in comparison with cv. 97009 under P deficient condition. In both rape cultivars, all the P fractions, including insoluble organic P, soluble organic P and inorganic P, increased with P levels in the medium. Low P stress reduced the concentrations of insoluble organic P in the roots of cv. 97009, but not cv. 97081. The ratio of soluble organic P (ester-P) in total P was higher in bottom leaves than upper leaves. Both the concentration and ratio of ester-P of cv. 97081 were higher than that of cv. 97009. The concentration of inorganic P in the roots of cv. 97081 was higher than that of cv. 97009; however, the ratio was much lower compared with cv. 97009. P-efficent cv. 97081 had greater activity of APase in roots and bottom leaves under low P stress than P-inefficient cv. 97009 although there was no significant difference in upper leaves between the two cultivars. The results suggested that the concentrations and distributions of P fractions and the activity of APase were closely related to P uptake and utilization efficiency of Brassica napus.