The invention discloses a biological sensor chip based on double-layer graphene. The biological sensor chip comprises a biological sensing layer, a prism and a silicon wafer, wherein the silicon wafer is clamped between the prism and the biological sensing layer; a fluororesin layer is arranged on a light refraction surface of the prism, and double-layer graphene layers are arranged on the light refraction surface of the silicon wafer. The biological sensor chip has the advantages that the double-layer graphene layers are additionally arranged on a waveguide structure to form a fully new sensor chip; the sensitivity of the biological sensor is greatly improved; the structure is simple, and the implementing is easy.