The wind power has the characteristics of intermittence and volatility. When it penetrates in power system, it will significantly influence the unit commitment of conventional transmission network with thermal units. Aiming at this problem, the method of unit commitment considering wind power paralleling in the power system is presented. Firstly wind active power forecast error statistics is made, and on this basis, its probability distribution model is built. Then, it combines the proposed model with the accumulated outage capacity probability table of traditional thermal unit to form unit accumulated outage capacity probability table considering wind power. Next, the probability table is introduced in the unit commitment Lagrange Relaxation in the way of analytical expression. The unit commitment model with wind power incorporated is formed, and traditional Lagrange Relaxation method is used to solve it. Finally, a real power system is taken as an example to verify the effectiveness of the proposed method.