A dielectric filter, comprising: at least two dielectric resonators (21, 22), wherein each of the dielectric resonators (21, 22) comprises a body made of a solid-state dielectric material, and an adjusting hole located on a surface of the body, the adjusting hole is a blind hole, configured to adjust a resonance frequency of the dielectric resonator on which the blind hole is located, the bodies of all the dielectric resonators (21, 22) comprised by the dielectric filter form a body of the dielectric filter, and the dielectric filter further comprises: at least one negative coupling hole, and a conducting layer covering the surface of the body of the dielectric filter, a surface of the adjusting holes, and a surface of the negative coupling hole; wherein each of the at least one negative coupling hole is located at a position of a surface of the body of the dielectric filter, at which two dielectric resonators (21, 22) of the at least two dielectric resonators (21, 22) are connected, the position at which the negative coupling hole is located is connected to the two dielectric resonators, and the negative coupling hole is a blind hole, configured to implement capacitive coupling between the two dielectric resonators (21, 22), characterized in that a depth of each of the at least one negative coupling hole is greater than each of depths of adjusting holes on two sides of the negative coupling hole. at least two dielectric resonators (21, 22), wherein each of the dielectric resonators (21, 22) comprises a body made of a solid-state dielectric material, and an adjusting hole located on a surface of the body, the adjusting hole is a blind hole, configured to adjust a resonance frequency of the dielectric resonator on which the blind hole is located, the bodies of all the dielectric resonators (21, 22) comprised by the dielectric filter form a body of the dielectric filter, and the dielectric filter further comprises: at least one negative coupling hole, and a conducting layer covering the surface of the body of the dielectric filter, a surface of the adjusting holes, and a surface of the negative coupling hole; wherein each of the at least one negative coupling hole is located at a position of a surface of the body of the dielectric filter, at which two dielectric resonators (21, 22) of the at least two dielectric resonators (21, 22) are connected, the position at which the negative coupling hole is located is connected to the two dielectric resonators, and the negative coupling hole is a blind hole, configured to implement capacitive coupling between the two dielectric resonators (21, 22), characterized in that a depth of each of the at least one negative coupling hole is greater than each of depths of adjusting holes on two sides of the negative coupling hole. at least one negative coupling hole, and a conducting layer covering the surface of the body of the dielectric filter, a surface of the adjusting holes, and a surface of the negative coupling hole; wherein each of the at least one negative coupling hole is located at a position of a surface of the body of the dielectric filter, at which two dielectric resonators (21, 22) of the at least two dielectric resonators (21, 22) are connected, the position at which the negative coupling hole is located is connected to the two dielectric resonators, and the negative coupling hole is a blind hole, configured to implement capacitive coupling between the two dielectric resonators (21, 22), characterized in that a depth of each of the at least one negative coupling hole is greater than each of depths of adjusting holes on two sides of the negative coupling hole.