In this paper

a hierarchical comprehensive evaluation method of power quality for the access of distributed wind power in the planning stage is proposed. First

this paper analyzes the main power quality index affected by the wind turbine and photovoltaic on the grid power is proposed. Then

the power quality index is stratified in accordance with the DG’s location and index of different index

and the fuzzy analytic hierarchy process（AHP）is used to determine the weight of each layer

in case of determining the weight of primary criteria

the D-S evidence theory is used and the users’ demands is added

then the weight is obtained by way of synthesis. Finally

the power quality assessment of different power network of DG position is performed based on layer analysis method. This method can not only evaluate in advance the grid power quality in the planning phase

but also evaluate effectively the operated grid. At the same time

it can also analysis the reasons of the poor power quality

and then reduce the waste of labor force and material resources and unnecessary economic losses.