The utility model relates to a special-faced double-exponential gradient sensor for cable partial discharge detection. The special-faced double-exponential gradient sensor is characterized in that the special-faced double-exponential gradient sensor for cable partial discharge detection includes a first double-exponential gradient quadrilateral metal patch 1 and a second double-exponential gradient quadrilateral metal patch 2 which are identical to each other, a dielectric substrate 3 which is made of an insulating material of which the dielectric constant ranges from 2 to 6, a rectangular metal shielding box 4, a coaxial line 5 and an N type connector 6. According to the four edges of the first metal patch 1 and the second metal patch 2, one end of one curve y=exp (ax) is connected with the upper end of a vertical short edge, and one end of the other curve y=exp (ax) is connected with the lower end of the vertical short edge, wherein the constants a of the two curves y=exp (ax) are different; the other ends of the two curves y=exp (ax) are connected with two ends of a horizontal edge; a slot which is shaped to correspond to the first metal patch 1 is formed at the top surface of the dielectric substrate 3; a slot which is shaped to correspond to the second meal patch 2 is formed at the bottom surface of the dielectric substrate 3; and when the projection of the slot at the bottom surface of the dielectric substrate 3 falls on the top surface of the dielectric substrate 3, the two slots are symmetric to each other with respect to the axis of the dielectric substrate 3. With the special-faced double-exponential gradient sensor for cable partial discharge detection of the utility model adopted, impedance gradient transition from an antenna receiving end to a feed transmission line can be realized, and therefore, antenna impedance matching can be improved, and the performance of the sensor can be improved.