The present invention provides a heat insulating and flame retardant felt, which is mainly prepared from high density polyethylene, added with glass fiber, wollastonite, montmorillonite, potassium titanate, zinc oxide, an ethylene-propylene-diene monomer, butadiene-acrylonitrile rubber, styrene-butadiene-styrene terpolymer, ethane-octylene copolymer, carbon nano-tube, calcium carbonate superfine powder, polypropylene grafting maleic anhydride, 2, 4, 6-tert-butyl phenol, and a colouring agent. Ingredients of the mixed materials for preparing the heat insulating and flame retardant felt are appropriate, which can overcome problems of poor toughness, low heat resistant grade and so on existed in normal polyethylene composite material felts.