The invention discloses a single-layer cast light reflex sheet material and a manufacturing method thereof. The single-layer cast light reflex sheet material is characterized in that the single-layer cast light reflex sheet material is manufactured by the melting, mixing and extrusion molding of 30 parts of A component by mass, 60-80 parts of B component by mass and 1-5 parts of C component by mass, wherein the A component is formed by mixing 3-48 parts of inorganic particles by mass and 5-50 parts of A resin by mass; the B component is formed by mixing 50-70 parts of B resin by mass and 1-20 parts of compatilizer by mass; and the C component is formed by mixing 0.05-1 part of organic ultraviolet absorbent by mass and 0.5-5 parts of antistatic agent by mass. The single-layer cast light reflex sheet material can be processed into light reflex plate members in devices for LED (light emitting diode) illumination, common daylight illumination, advertisement signboard lamp boxes and the like by modes such as cutting, folding, blistering or punch forming, and has a good effect.