An embodiment provides a manufacturing method of a polycrystalline silicon layer, including: forming a first amorphous silicon layer on a substrate; doping an N-type impurity into the first amorphous silicon layer; forming a second amorphous silicon layer on the n-doped first amorphous silicon layer; doping a P-type impurity into the second amorphous silicon layer; and crystalizing the n-doped first amorphous silicon layer and the p-doped second amorphous silicon layer by irradiating a laser beam onto n-doped first amorphous silicon layer and the p-doped second amorphous silicon layer to form a polycrystalline silicon layer.