The invention discloses a thermal power dual-layer peak adjustment method. The method comprises: S1, partitioning a peak adjustment output range for each thermal power unit, wherein different output ranges correspond to different integer variable values; S2, giving out a load curve of thermal power; S3, solving an integer variable, namely, solving a first layer; S4, solving an output of each thermal power unit, namely, solving a second layer; and S5, giving out the output and equivalent start-stop peak adjustment capacity of each thermal power unit according to a solving result of a second-layer thermal power peak adjustment model. The method has the following advantages: each peak adjustment output range of the thermal power unit can be considered; a mixed integer programming problem can be decoupled into an integer programming problem and a linear programming problem, so that the computing time is shortened; and the equivalent start-stop peak adjustment capacity of the thermal power unit in a peak adjustment scheme can be given out, so that the thermal power peak adjustment cost is macroscopically described.