A method of manufacturing a thin film transistor array panel is provided, which includes: depositing an amorphous silicon layer on an insulating substrate; converting the amorphous silicon layer to a polysilicon layer by a plurality of laser shots using a mask; forming a gate insulating layer on the polysilicon layer; forming a plurality of gate lines on the gate insulating layer; forming a first interlayer insulating layer on the gate lines; forming a plurality of data lines on the first interlayer insulating layer; forming a second interlayer insulating layer on the data lines; and forming a plurality of pixel electrodes on the second interlayer insulating layer, wherein the mask comprises a plurality of transmitting areas and a plurality of blocking areas arranged in a mixed manner.