The invention relates to a single-phase instant artificial grounding short-circuit test system for a power transmission line, and belongs to the technical field of high-voltage test equipment and measuring. The single-phase instant artificial grounding short-circuit test system comprises metal downleads, a metal arc striking line, a current transformer, a measuring instrument and the like. The two metal downleads are connected with an overhead line of the power transmission line respectively, and a metal bar is fixed between the two metal downleads. A traction insulation rope is connected with a line collecting device, the other end of the traction insulation rope is connected with the metal arc striking line, the metal arc striking line is connected with a power transmission tower through a grounding connecting line, the grounding connecting line is laid on a metal plate, the current transformer is connected to the grounding connecting line in series and is laid on an insulating plate, and a secondary side is connected with the measuring instrument. The single-phase instant artificial grounding short-circuit test system has the advantages of being simple, convenient and good in safety, line collecting is conducted in a power-driven mode, and it is guaranteed that only instant artificial grounding short circuit can be made in the test without continuous failures, and safe operation of a power grid is not affected.