Based on the current situation that the thermal power units in China are mostly coal-fired units， and considering the fact that dispatching center cannot directly obtain unit's coal consumption function after the implementation of electricity market， the unit commitment model associated with electricity market and energy-saving dispatch is established by involving the carbon dioxide emission function instead of the energy consumption function . The Lagrange relaxation method is used to solve this model. In this model， the unit's generating willing is illustrated by generating unit's bid; the consumption and emission reduction requirement of power systems are described by energy consumption function. An algorithm based on iterating price weighting factor is employed to establish the optimal unit commitment scheme. In this paper，the emission function is approximated by polynomial curve fitting techniques. The influence of measurement error on unit commitment is analyzed as well. The results of case study show that the proposed model and algorithm can facilitate the better coordination between energy consumption and economic indicators， and a broad application prospect is expected.