The invention discloses a supercapacitor composite separator material of high mechanical strength. The supercapacitor composite separator material is prepared by the raw material of the following parts by weight: 35-40 parts of polyvinyl alcohol fiber, 33-35 parts of mekralon, 10-13 parts of polyacrylonitrile powder, 30-32 parts of acetone, 72-75 parts of N,N-dimethyl formamide, 8-10 parts of water soluble PVA fiber of 70 DEG C, a moderate amount of water, 13-15 parts of calcium carbonate, 5-7 parts of glass fiber, 7-9 parts of mica powder, 2-3 parts of oxidized polyethylene wax, 1-1.2 parts of sodium dodecyl benzene sulfonate, 2-3 parts of waterborne polyurethane emulsion, 3-4 parts of animal glue and 1-1.5 parts of polydimethylsiloxane. The processed calcium carbonate, the glass fiber and the mica powder are added in the preparation process of nonwoven fabric and evenly dispersed in slurry so that the mechanical strength of the prepared product can be further enhanced, the product is enabled to be anti-tensile and is not liable to fracture, and thus the supercapacitor composite separator material of high mechanical strength is the supercapacitor used composite separator material of excellent performance.