A manufacturing method of a thin film transistor array panel includes: simultaneously forming a gate conductor and a first electrode on a substrate, using a non-peroxide-based etchant; forming a gate insulating layer on the gate conductor and the first electrode; forming a semiconductor, a source electrode, and a drain electrode on the gate insulating layer; forming a passivation layer on the semiconductor, the source electrode, and the drain electrode; and forming a second electrode layer on the passivation layer.