Abstract: Under the condition of greenhouse, three phosphorus efficient Arabidopsis and four phosphorus inefficient Arabidopsis obtained from several screening experiments were examined further using the criterion of phosphorus efficient coefficient, e.g. the ratio of yield at phosphorus deficient level to phosphorus normal level, with solution culture experiments. The results showed that the phosphorus efficient coefficient at seedling stage was identical to that at mature stage, which indicated that phosphorus efficient Arabidopsis showed the characteristics of phosphorus efficiency at seedling stage and it was effective to screen phosphorus efficient Arabidopsis at seedling stage. The nutrition mechanism of phosphorus efficient Arabidopsis might be attributed to longer root, higher ratio of root to shoot, more phosphorus accumulation, and higher activity of acid phosphatase at phosphorus deficiency.