This paper uses LCOE method to compare the average cost of long-term investment between renewable energy projects and traditional energy projects by choosing wind power and typical projects of traditional coal-electric power respectively，and the results show that wind power projects have obvious cost advantage over coal-electric power projects even though encouraging policy subsidy of renewable energy and environmental externality of traditional coal-electric power are not considered，which denies the cognition that renewable energy has too much cost，that the basic factor hampering renewable energy such as wind power is not power cost but is the restriction from the processing capacity and transmission capacity of power grid， and that in the areas of China with rich wind power，currently，majority of the areas have small power load capacity and large-scale wind power faces the difficulty in the process capacity of local power grid. Thus，China should enlarge the investment in intelligent power grid construction，strengthen the construction and maintaining of matched facilities for wind power and develop wind power around the places with the power demand centers.