The intrinsic layers with different thickness were deposited on amorphous n-type layers and microcrystalline n-type layers respectively, and all samples were prepared by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD). The effect of different n-type layers on structural properties of i-layer was studied. It is concluded that the highly microcrystalline n-layer can reduce the thickness of incubation layer, promote structural uniformity of i-layer and improve the performance of n-i-p μc-Si:H thin film solar cells.