Provided is a lead wire supporting device for pressure-tight test, comprising a fixing base, a universal control device, and a support bar. The fixing base is fixedly provided with a spliced pole, and a universal control joint is assembled to the spliced pole. One end of the support bar is assembled with the universal control joint. The lead wire supporting device for overpressure resistance test is advantageous in that during lead wire arrangement, the variable-diameter assembly of the support bar sleeves a second connecting block. The universal control device can control the position of the support bar in horizontal and vertical directions. The support bar supports the lead wire used for the overpressure resistance test, which prevents the operation of steering clear of the device. The arrangement of the lead wire can be completed at one time, and the time of the whole overpressure resistance test can be shortened, and work efficiency is greatly improved and labor is saved.