The invention provides a halogen-free environmental-protection H-level heatproof tri-layer insulated wire. Each of first and second insulation layers uses PPS and silicone rubber, and a third insulation layer uses PA and a stabilizing agent. On one hand, the insulation layers are modified to improve the high temperature of the insulation layers, and it is proved by detection that the insulated wire can be used normally after aging baking at the temperature of 260 DEG C; and on the other hand, the insulated strength, flexibility and aging resistance of the insulation layer can be improved effectively, and it is proved by detection that the insulation layers after aging baking at the temperature of 260 DEG C are prevented from cracking, falling off or hardening when being folded for multipletimes.