The establishment of a cost model for complex energy systems based on thermoeconomics can provide technical and economic evaluation indicators for complex energy systems. At the same time, to integrate more renewable energy into the grid, complex energy systems must participate in deep peak shaving. To evaluate the technical-economic performance of complex energy systems involved in deep peak shaving, a novel thermoeconomic cost construction method is proposed based on the production structure diagram, using the gas-steam combined cycle system as an example. these can effectively avoid the derivation error of high-dimensional models, improve the modeling and calculation speed, and obtain the variation trend of system thermoeconomics cost under load changes and operating parameter changes. The results show that the external and internal factor can change the power generator thermoeconomic cost. the power generation cost of the system increases with increasing natural gas price and environmental temperature When the compressor pressure ratio increases, the power generation cost of the system also increases. At 100% load, the power generation cost reaches its lowest value when the exhaust temperature is equal to 615°C.