CO2 emissions trading is the main scheme for mitigating greenhouse gas（GHG） emissions and has been or is going to be implemented in some developed countries or regions. Given this background， the CO2emission price in an emissions trading market is evaluated using an optimization approach similar to the well-developed stochastic production simulation method. Then assuming that the probability distribution functions of rivals' biddings are known， a stochastic optimization model is presented within the framework of a chance-constrained programming approach. It can be used to build risk-constrained optimal bidding strategies for a generation company. The corresponding solution method is also developed for this optimization model. Finally， a numerical example is given to demonstrate the feasibility of the developed model and solution method. The optimal bidding results are compared for two situations with and without the CO2 emissions trading schemes.