This study investigated the effects of glucose and sodium propionate supplementation (as the second carbon source ) on the bacterial biomass, polyhydroxybutyrate ( PHB ) and poly- ( hydroxybutyrate-co-hydroxyvalerate) ( PHBV) synthesis, and PHBV content in Ralstonia eutropha under phosphorus-limited conditions. Fermentation was performed in a 3-L fermenter. Batch fermentation was conducted in the initial phase, followed by continuous fermentation in the exponential phase. In the culture containing glucose as the carbon source, the biomass of bacteria, the amount of PHB biosynthesis, and the content of PHB in cells initially increased and then decreased when the dilution rate was decreased. The highest biomass of 7.31 g/L was obtained at a dilution rate of 0.101 h-1 . The highest amount of PHB biosynthesis and the highest content of PHBV in cells were 1.97 g/L and 27.9%, respectively, which were obtained at a dilution rate of 0.151 h-1 . The highest average glucose consumption rate of 3.04 g/L·h obtained at a dilution rate of 0.151 h-1 provided adequate carbon content for microbial growth and PHB synthesis. A decrease in the dilution rate resulted in the reduction of the flow rate of feed, supply of the carbon source, amount of PHB biosynthesis, and content of PHB in bacteria. When glucose was used as the carbon source, sodium propionate was added as the second carbon source, and the dilution rate was reduced, the biomass, PHBV synthesis, PHBV content in cells, and hydroxyvalerate ( HV) content in PHBV increased and then decreased. When the dilution rate was 0.0531 h-1 , the average biomass was 6.70 g/L. At a dilution rate of 0. 0851 h-1 , the PHBV synthesis, PHBV content in cells, and HV content in PHBV were the highest (1.90 g/L, 29.4%, and 10.5%, respectively) . The cell yield coefficient was 0.804 g/L · h at a dilution rate of 0.165 h-1 . The yield coefficients of HB (hydroxy butyrate) and PHBV were the highest ( 0.145 and 0.162 g/L·h, respectively) at a dilution rate of0.0851 h-1 . The contents ofHB, HV, and PHBV in the residual biomass were the highest when the dilution rate was 0.0851 h-1 , indicating that a dilution rate of 0.0851 h-1 , a feed flow rate of 110.7 mL/h, and an adequate carbon source were provided to synthesize HB and HV. The low feed flow rate of 69.0 mL/h at a dilution rate of0.0531 h-1 could not provide an adequate carbon content for the synthesis ofHB and HV.