Abstract: As power systems are faced with restruction, more and more attention has been paid to the comprehensive competitive power of a plant, which can be improved by using the plantwide optimal load dispatch. At present, the load was distributed based on coal consumption characteristics in order to minimize the total costs. The optical load dispatch model with velocity or stability constraints had been proposed, but it was solved by choosing a weight between the total costs and the response speed, which does not reflect the practical requirement of load dispatch. A new load dispatch model with velocity constraint is presented in this paper. The total costs are minimized with a specified response speed of a power plant, which is practical and help ful to improve the plant comprehensive competitive power.