The maximum installed capacity of wind power integrated into a certain power grid is the most important concern for the power company at the wind power planning stage. Based on the characteristics of power source and load in Liaoning power system， the possible problems in adjusting supply and load with wind farms in operation is analysed. By considering spinning reserve capacity during peak load time and thermal power plants running at minimum capacity during valley load time， the calculation method to determine the maximum installed capacity of wind power integrated is put forward， and the formula for calculation is summarized. The maximum installed capacity of wind power integrated in each year of 2010， 2012， 2015 and 2020 is given. It is pointed out that the acceptable capacity is less than the planned capacity. At last， the specific measures to increase the capacity of wind power are proposed.