Abstarct: Limitation in fossile resources is the challenging issue of governments in the recent decades. As a result the government intend to reduce the use of fossile resources and increase the use of renewable resources. such as wind power that draws attention the electric utility in order to generate electric power. In this thesis, a stochastic optimization model for unit commitment scheduling in order to determine hourly power production of each unit has been used, this scheduling has been performed with consideration of unit constraints and transmission line power flow limit. In this project, the level of wind has been assumed as a normal probability distribution function which has been modeled by scenario tree. The probability of each scenario and the value of loss load are also considered in the objective function. Unit commitment programming has been done applying fuzzy optimization with consideration of load uncertainty and the uncertainty of wind power production. In addition, the impact of wind presence on thermal unit emission have been investigated and a multi objective programming approach for considering both objective functions of cost and emission is proposed. Unit commitment scheduling with stochastic security criterion has been examined on a 3-bus example system and IEEE-RTS system. Unit commitment scheduling with the aim of simultaneously reducing the operational cost and emission of thermal units has been performed on the IEEE 30-bus test system and IEEE-RTS system. Also the proposed fuzzy optimization method has been simulated on the IEEE 30 bus system. Simulation results indicate that the proposed methods have better results compared to the previous methods