The invention discloses an acid-absorption and high-strength supercapacitor diaphragm material and a preparation method thereof, which belongs to the field of the preparation of electrochemical materials. The invention provides the acid-absorption and high-strength supercapacitor diaphragm and a preparation method thereof. Compared with the prior art, according to the preparation method of the invention, metal oxide particles and ceramic fibers are added into the matrix fibers to obtain anticorrosive supercapacitor diaphragm material which is relatively good in strength; and by adding the SAFsuper-water-absorption fibers, the diaphragm material contains rich pores and larger specific area, and has good water absorption performance and lower internal resistance.