The characteristics of wind power such as wave properties, intermittence, seasonal nature, counter regulation and so on have negative effect on power grid; grid-connected wind power on a scale is limited. To aim at the problem that there lacks quantification evaluation method on grid-connected wind power, an comprehensive evaluation index system concerning safety, adequacy, power quality and economy on the power grid which wind power is accepted. By using current advanced fuzzy interval analytic hierarchy process (FIAHP) , analyzing index such as static stability reserve coefficient, peak margin and transmission reliability margin and so on, coming up with the potential risk, thus on the condition of system safety and steady operation, penetrating power can be maximization, utilization rate improved. At last, analysis of the example proves that the evaluation index system and evaluation method is scientific and feasible.