The objective of this study was to examine the response of root traits, morphological indexes, and nutrient use efficiency of Chinese fir seedlings to heterogeneous distribution of available phosphorus (P) in soil. Seedlings of half-sib family cultivated in single seed plantation of Chinese fir seed orchard were selected as research material, and indoor pot experiments were conducted. The pot experiments involved three P supply levels including low (8 mg/kg), normal (16 mg/kg), and high P treatment (32 mg/kg). Two kinds of P supply methods (heterogeneous and homogeneous P supply) of each P supply level were used to apply P to roots of single plants. The results showed that:1) root length, root biomass, root-shoot ratio, root and whole plant P use efficiency of Chinese fir under low P supply were significantly higher than those under the normal or high P supply, while average root diameter was the opposite. With the increase of P supply level, there was no significant difference in seedling height and aboveground biomass of Chinese fir, but the specific root length showed a decreasing trend. 2) The seedling height, root length, root surface area, specific root length, aboveground biomass, and whole plant P use efficiency were significantly higher in the heterogeneous P supply treatment than those in the homogeneous P supply treatment, while the average root diameter and root-shoot ratio were the opposite. In conclusion, the morphological plasticity of Chinese fir roots could be significantly enhanced under low concentration and heterogeneous P supply, thus optimizing the spatial distribution of roots in nutrient-heterogeneous soils, and maintaining the normal growth of shoots by improving the P use efficiency of roots.