The invention provides a polyethylene laminated metal composite isolation membrane which comprises the following components in percentage by weight: 55-70% of high temperature resistant inorganic substance, 10-30% of polyethylene, 3-10% of coupling agent and 5-10% of lubricant. The polyethylene laminated metal composite isolation membrane is prepared through the following steps of: feeding the components in proportion, mixing at a high speed, adequately dispersing, carrying out rubbing, plasticization, extrusion and granulation to obtain master batches, and extruding and calendering the master batches to obtain the polyethylene laminated metal composite isolation membrane with the specification of 0.1-0.5mm. The obtained polyethylene laminated metal composite isolation membrane is filled with the high temperature resistant inorganic substance, the filling rate is proper, the thickness specification is moderate, the production process is simple, the quality of the laminated metal composite can be remarkably improved and the production efficiency can be greatly improved; and with the thickness of 0.1-0.5mm, the filling rate of 55-70% and the gram weight of 500-800g/m<2>, the isolation the membrane is suitable for the assembly production of composite billets.