Considering carbon emission allowance investment cost under the cap-and-trade carbon emission trading scheme，a carbon emission allowance trading model is established based on generation cost model.According to profitability loss result from energy consumption of carbon capture system，the power selling loss is defined and the carbon capture level optimization model is further proposed.The different resources installed with carbon capture system are used as reference to calculate the changes in carbon capture level with net power under different carbon emission allowance prices.The sensitive internals of carbon emission allowance that boost GenCos anticipating in carbon capturing under both carbon trading model and carbon capture level optimization model are acquired.Comparison analysis on spot and future price of carbon emission allowance under European Union Emissions Trading System shows the proposed carbon capture level optimization model is reasonable，feasible and effective.