Abstract: To explore the adaptive response to soybean root architecture indicators in low-phosphorus stress, to study the relationship of root architecture indicators with P efficiency. This test selected three "P-inefficient" soybean genotype D3, D17 and D18 and the "phosphorus efficiency" soybean genotypes D34, D37 and D38, A field experiment was located high and low phosphorus treatment, phosphorus efficiency of soybean genotypes and root architecture of the relationship were studied. The results showed that the high phosphorus treatment, the soybean root architecture for the test and the root dry biomass were no significant differences; in the low-phosphorus treatment, the difference between the various genotypes to reach significant level. Correlation analysis showed that root length, root surface area and root biomass and aboveground dry biomass reached significant or highly significant positive correlation, the correlation coefficient of root diameter and phosphorus efficiency does not meet the significance level. Low-phosphorus stress, the root length, root surface area and root biomass of affecting plant phosphorus efficiency, root diameter less impact on the efficiency of phosphorus. Therefore could be the root length, root surface area as a selection of phosphorus efficiency of soybean an important indicator , the root biomass as a supplementary screening index.