Abstract: In order to study the change rule of coal consumption of cogeneration units under different heating load distributions in the whole working condition, and realize the goal of deep energy saving and carbon emission reduction in power plants, two 630 MW cogeneration units were taken as the research objects. The EBSILON software was used for modeling, and the different heating load distribution schemes of single and double units were studied and analyzed based on the Freuger formula and the principle of caloric method. It is found that there is a critical heating extraction steam flow point in the influence of thermoelectric load change on coal consumption of a single unit. When the heating flow is less than the critical point, the greater the electric load, the higher the thermal efficiency of the units. When the heating flow is greater than the critical point, the smaller the electrical load,the higher the thermal efficiency of the units. For two operating units, when the heating load is distributed centrally to one unit, the coal consumption of the whole plant under different working conditions is the least, and the energy saving effect is better. It is of great significance to find the best way of heat supply distribution to reduce the coal consumption of power plants, save energy and reduce emission and respond to the national “carbon neutral” policy.