The invention relates to the field of explosive processing, and in particular relates to a fiber-reinforced rubber explosive and a preparation method thereof. The problems in the existing explosive processing technology that the mechanical properties are poor and the process is complicated and has dangerousness are solved. The fiber-reinforced rubber explosive is composed of the following raw materials in parts by mass: 5-20 parts of rubber, 55-90 parts of high explosives, 2-5 parts of chopped fibers and 3-10 parts of additives. The invention has the beneficial effects that the prepared explosive has excellent mechanical properties and adjustable detonation velocity and detonation output energy; and with the adoption of recyclable rubber powder and chopped fibers, recycling of wastes is realized; the fiber-reinforced rubber explosive has the advantages that the production process is simple, the components are uniformly mixed, and batch production can be realized; and the fiber-reinforced rubber explosive is used in the explosion working industry and can also be used in other special industries, particularly operations in low-temperature environments.