The stoichiometric matrix of a simplified metabolic network in Bacillus Subtillis was constructed from the flux balance equations, which were used for reconciliation of the measured rates and determination of the inner metabolic rates. Thus more reliable results of the true and empirical maintenance coefficients were obtained. The true maintenance coefficient is linearly related to the specific growth rate and changes with the P/O ratio. The measured biomass yield of adenosine triphosphate(ATP) is also linearly related to the P/O ratio.