Emission Trading Schemes(ETS) has been implemented in electricity industrial activities. A large number of existing and potential GENCO are subject to ETS and targeted for emission reduction. A dynamic decision making model is proposed to deal with the multimarket trading problem for GENCO. During each trading period, the operation of GENCO is divided into production process and trading process. These two processes are considered dynamic and stochastic so that the results of decision making are given process by process for each planning period. To solve the multi-period stochastic optimization problem, Differential Evolution(DE) algorithm is adopted to give the results of each period. Comparisons between different scenarios show that the proposed model can provide good tradeoff between profit-making and emission reduction.