The utility model discloses an adjustable insulating supporting device is used to four rails of urban traffic, which comprises a bracket, be provided with the layer board on one side of the support, the layer board includes supporting part and mounting panel, mounting panel and support side contact, supporting part and track side profile of surface phase -match, install the cassette on the mounting panel, the cassette includes clamping part and supporting part, jack catch on still installing on the mounting panel, go up jack catch shape and track side profile of surface phase -match, clampingpart and the fixed backward flow rail of supporting part cooperation, go up jack catch and the fixed power supply rail of supporting part cooperation, at the supporting part, the clamping part, face with rail contact on supporting part and the last jack catch has all imbedded nylon cushion block, support and mounting panel contact surface are sawtooth surface, be equipped with the bar hole of fixed mounting board on the support, be equipped with on the mounting panel with the relative mounting hole in bar hole, be equipped with the connecting hole that matches with the mounting hole on last jack catch, be equipped with a set of increase creepage distance's recess on the cassette.