The invention discloses a method for improving the brazing strength of a tungsten-copper part. The method comprises the following steps of S1, pressing of a tungsten blank; S2, forming, wherein the pressed tungsten blank is placed in a graphite crucible, a copper block needing infiltration is placed on the tungsten blank, then emery powder is adopted for filling and is tamped, and a pre-sintered part is obtained; S3, sintering, wherein the formed pre-sintered part is put into an atmosphere protection molybdenum wire furnace to be sintered at a high temperature, and a tungsten-copper alloy is obtained; S4, sand blasting, wherein after the sintered tungsten-copper alloy is discharged out of the furnace, sand blasting is carried out to remove the emery powder on the surface, and a copper-clad layer of 0.01-0.1 mm is naturally formed on the surface of the tungsten-copper alloy; and S5, vacuum brazing, wherein vacuum brazing is conducted on the tungsten-copper alloy obtained after sand blasting and stainless steel or a Kovar alloy. According to the method, the ultrathin copper-clad layer of 0.01-0.1 mm is infiltrated on the surface of the tungsten blank, the welding strength between the tungsten-copper alloy and the stainless steel or the Kovar alloy is effectively improved, the brazed rate is increased, and the welding defect caused by non-infiltration of a tungsten-copper material is effectively avoided.